It is not possible to upload a manual for every kind of manual typewriter ever made -- or even one for each brand.  But, for those new to manual typewriters, we can provide some details applicable to the operation of EVERY manual typewriter.  Here is a primer that we call our ONLINE TYPEWRITER MANUAL.
Mechanical typewriters that anyone will really use today all have some things in common.  They all have a CARRIAGE, which is the part of the typewriter that moves from right to left as you type, and which holds the paper.  In this shot, it's naturally on the left.  You use the KEYBOARD to actually write, as well as to provide spaces between characters.  Easy to figure out.
Here are some parts and controls.  1) CARRIAGE, the part that moves to the left as you type and which must be returned to start the next line down.  Moved by a spring-driven drum called a mainspring; the mainspring pulls the carriage to the left with a drawband.  As you type each character, or space between them, a precision-built ratcheting device called the escapement allows for the proper precise travel of the carriage.  2) Some machines have a flip-up PAPER ARM to support the sheet as you go along.  Nice to have, but not a necessity.  3) MARGIN STOPS determine just how far the carriage can move in either direction; this allows for proper borders on both sides of the printed sheet.  As you approach the right-side margin, a bell will ring indicating you're getting close and should be careful to either hyphenate a long word or just go back for the next line.  Left-side stop controls carriage position when you return the carriage.  4) the PAPER BAIL holds the paper down on top of the cylinder, or PLATEN, that it's wound around.  Some machines have rollers on the bail, some don't; some have a scale marked on the bail, and some don't; on some, the bail just flips upward, on others it pulls toward you, and on some it can do either.  Some don't even have a paper bail and use individual holders or fingers, one on either end of the carriage.  5) Two levers found on the right side of this machine's carriage are the CARRIAGE RELEASE, which when depressed allows you to move the carriage freely either direction, and the PAPER RELEASE, which releases tension on the paper so that it can either be straightened out or else removed. 6) The PLATEN KNOBS allow you to turn the platen to feed paper or move it up or down where you want it, or remove it.  Some have only one knob, on one side or the other, but the vast majority have two.  7) The key by this number is the BACK SPACE key, which moves the carriage one space at a time backwards.  8) The large, unmarked key seen here is the right-side SHIFT KEY.  You must use this in order to get capital letters, or else to get the various characters seen printed on the upper parts of the top row of keys.  You depress it, or the one on the other side, strike the character, and then release it.  This key either moves the whole carriage or else moves the type bar segment.  If the former is the case, then the machine is called "Carriage Shift," and if the latter case it's called either "Segment Shift" or else "Basket Shift," the terms being perfectly synonymous.  9) The SPACE BAR moves the carriage along space by space just as if you were typing but no character is printed.  10) Here we see the left side shift key, and just above it is the SHIFT LOCK key.  This key locks the shift mechanism in place to allow easier typing of a large number of capital letters.  Some machines have the shift lock on the left, some on the right and some have one on both sides.  You have to press one or the other (or either) shift key to kick out the lock mechanism. 11) The key under this number is the MARGIN RELEASE key.  It allows the carriage to bypass the margin stop settings you set up back in no. 3 above.  If you're in the middle of a word, near the right side, and the bell has rung and then the carriage stops and you cannot type, you are against the right-side margin stop; press the margin release key to finish the word and then return the carriage.  12) Here we see a lever with three colored dots by it.  This is a RIBBON SELECTOR, which determines what color the machine types in; black or red.  Many machines have a white dot, for use in cutting stencils, but this kind of work is long-gone and this position is no longer necessary in this day and age.  Some machines only type in one color, and naturally if you put an all-black ribbon in a machine that does have a selector then you can get twice the time out of it -- when the upper part runs out on the ribbon, you can either remove and invert the ribbon or just use the ribbon selector to type on the other half.  13) This lever is the CARRIAGE RETURN LEVER, also sometimes called a "line-space lever."  You use it to move the carriage back to start another line of writing.  It is connected to the line-space mechanism that operates when the lever swings, and this moves the paper up one line to start over at the right HEIGHT when you return the carriage to start the NEXT LINE.  14) This is the region of the LINE SPACE mechanism, and usually includes a selector switch so that you can either single-space, double-space or even on some machines either triple-space or include half-line spacing.  There's a wide variety out there so check this out closely on any given machine.  15) The RIBBON is what contains the ink that gets pressed onto your paper.  This one has both black and red, which is proper since this machine has a black-red ribbon selector.  It is wound on spools, and moves automatically from one to the other so that fresh ink is available for each strike.  The SEGMENT (16) is used to mount all of the TYPE BARS (17) which are those parts that hold, on their ends, the type slugs that actually go up and hit the ribbon.  Each type slug has two characters on it in the example machine seen here.  The slugs are most often soldered on, but on old machines can be wedged on or else fitted with pin and slot connections.  Under the TOP COVER, or sometimes RIBBON COVER (18) are the ribbon spools, and internal workings; keep the cover on to prevent dust from getting in.  Some machines have a device for allowing variance of key tension, to suit individual taste, and this is often found as a lever or dial under this cover.  There are very many designs of cover; be careful upon removing this the first time, as some pull straight up, some hinge at the front, some hinge at the back, and some even pull straight forward or lift up on linkages.  Use care and a little gentle force and you'll get it off no problem.
Many kinds of portable typewriters have a CARRIAGE LOCK that serves to protect the machine's mechanical workings when it's being moved around.  You should always engage it when you move a machine around, and certainly use it when the machine is put in its case.  There are MANY designs of lock used over time, but they're mostly easy to figure out. 
If you are buying an old typewriter to use, be careful.  There are some machines out there which were made during the Great Depression of the 1930's, which were stripped of features so that they were affordable.  Some of them, like this Royal Signet, only type in capital letters -- look and you will see that the machine has no shift keys.  It also has no back-space key, and no margin release key.  These kinds of things make for a very rustic typing experience but end up being a hindrance for real work.  In other words, if you're dealing with one of these, there will be a LARGE number of things we'll talk about here that you will NOT be able to find on your machine.
Here is another diagram for a machine similar to that shown in our numbered picture above.  This one has more options.  Number 19 is a TOUCH REGULATOR, which is seen below right.  It is under the top cover.  The "+" setting is for harder touch.  Numbers 21 and 22 on the diagram, shown below close-up, operate the TABULATOR.  This allows the carriage to fly right to a given point when the TAB key is pressed; you can set the stop points using the rocker (you push the + end) and clear them with it as well (using the - end.)  The lever on the carriage, also shown, clears ALL stops at once.
Now that you have the basics, you can proceed to the website I've set up for support of typewriter owners who are also typewriter USERS.  Click here to get to my TYPEWRITER ANNEX site for much more operative information, and/or read on below.
Some advanced typewriter terminology.
Here's a diagram of the type-action design for a typewriter.  The "user" side is on the right, and the PLATEN is on the left.  16 is the KEYTOP, which can be built up of pieces (a glass insert, over a paper LEGEND showing the character, with both held down by a nickel or chrome KEY RING) or can be solid with the letter painted on or cast-in.  It is attached to the KEY STEM portion of the KEY LEVER 15.  The key lever is that first lever which operates as a result of the key being pressed.  In this complicated design, there are several intermediate levers (13 first in yellow, then 11 in blue and 6 in red) which operate before you get to the actual typing.
In this machine, the only function for yellow lever 17 is to ensure vertical motion of the keytop and key lever (and provide an attachment point for a SPRING that will help return everything to normal position when the key is released.)  Finally we get to the TYPE BAR, shown in green, on the upper end of which we see the TYPE SLUG (5) with two characters on it.   Near number 8 in gray lines is represented a rest for the type bars.  3 in gray lines is a cut-away view of the SEGMENT that we saw in the earlier drawing.  (These aren't the same typewriters, by the way.)

OPERATION:  Key top 16 is depressed and moves straight down, swinging links 13 and 17.  Link 13 hinges about the left-most point 14 seen here, pushing link 11 down along a pin in slot 12.  As link 11 moves down and in, motion is imparted to lever 6 which rotates about pin 8, bringing its lower end upward.  This causes pin 7 in the slotted end of the type-bar to raise the type bar until at maximum travel type slug 5 is in contact with the platen.  Spring near point 18 helps return the entire linkage to rest position following operation.
Here we have drawings, from above and from the side, for a machine that is extremely simple compared to that above.  In this design, on the left, we can see that each horizontal row of keys is hinged on a long metal shaft called a DOWEL ROD.  Those rods are all mounted in a DOWEL PLATE located right behind the key levers.  Above, we see the design with one key depressed in see-thru or "phantom" view.  The key lever is really a kind of V shape, and as the key top moves down in an arc, hinging around the dowel, its other end pulls on a link rod, or reach rod, which is directly connected to the bottom end of the type bar.  So, then, as compared with the complicated design above we have THREE moving parts for each key when typing is performed.

This has advantages and disadvantages; a machine this simple has a much cheaper, duller feel, but also is much less likely to break and is easier to lubricate. 
Click here for more designs; use your browser back button after.
...enough of that; let's get TYPING!
GENERIC TYPEWRITER DIAGRAM
IMPORTANT NOTE:  As you probably are aware, there is an enormous variety of typewriter brands and models available, produced over a hundred or more years.  Naturally, they all differ in options like tabulators, paper tables / arms, ribbon selectors and many more.  The particular machine you are trying to operate may have some features seen on these pages, may omit others and even may have some you will NOT see.  What is important to today's author is that the vast majority of the machines out there, once in good operating condition, really do work for all intent and purpose without such things as a tabulator.  In modern use, for the author, the only thing this is good for is paragraph indentation, which is easy enough to do with the space bar.  Keep this kind of thing in mind as you continue on with the directions below, and do NOT expect that "a good machine should have this or that feature."  That is NOT the case.
by WILL DAVIS
Keep this in mind regarding options and operations....
PREPARE THE MACHINE FOR USE.  Remove the machine from its case; some have snap-over lids, some have actual cases that you can remove the machine wholly from, and some remain attached to the case base.  Unlock the carriage, raise the return lever, deploy the paper support arm if fitted, and check that the ribbon is in the vibrator properly. 

Make sure the machine is on firm, level surface at the proper height and that it cannot move around.
INSERT PAPER.  Line up the left edge of the paper with the "0" mark on the left carriage end; some machines have a paper guide here.  Placing the paper behind the platen, turn the platen knob to feed the paper through the carriage.  Make sure it comes out the front level; here, we see the paper just barely above the front scale, and it's been checked and leveled.  You can use the paper release for this.  Check the position of your left and right margin stops.
JUST ABOUT READY, I've rotated the platen so that the paper is high enough for me to begin typing -- in other words I've left the proper amount of space at the top of my page.  I've checked that the side edges of the paper match -- another way to ensure straighness.  The carrriage is at the left margin stop, and I've set the line-space lever (visible more clearly above) at single-space. 
RETURN THE CARRIAGE.  I've finished my first line, and return the carriage briskly.  It hits the left margin stop, and the actuation of the line-space / carriage return lever moves my paper to the next line. 
This machine is an example that has the left-edge paper guide.  These come in many styles; on this one, you use the little pointer at the right end of the guide to indicate where you want the actual left end to be in terms of the carriage spacing.  As we see here, I've positioned it with the pointer at "0" on the scale on the paper table.  This machine also has a different style line-space lever that pulls toward you.  Also, the margin release is not a conventional key; it's the little silver button at the keyboard's top left side. 
If your paper will not feed straight, then operate the paper release and feed it through while turning the platen.  Get it in the proper position as shown above, earlier, and then return the paper release to the operating or normal position.  This should help.  Also, very old machines may have worn-down rollers inside the carriage where you can't see them; in this case, it is sometimes helpful to use two sheets of paper.  This increases the thickness a bit and will help allow the rollers to grab.  You can re-use your "backing" sheet over and over.