Answer 1: A "registered" trademark symbol is the capital letter "R" with a circle around it. And it's always in superscript, to the immediate right of the word or phrase that has been trademarked.
Example: Coca-Cola®
However, the fact that there's a "registered" trademark, as opposed to just a plain ol' trademark, suggests that there are other kinds of trademarks. And that's a correct assumption... there are.
An unregistered trademark is the capital letters "TM" to the immediate right of the trademarked word or phrase, also superscripted.
Example: Coca-Cola™
There's also such a thing as a "service mark," which is the capital letters "SM" where the "TM" is seen in the immediately-above example.
None of this is to be confused with a copyright notice, which is the capital letter "C" with a circle around it, but not usually superscripted; and usually follows the word "Copyright" and appears before the year in which the copyright is claimed.
Example: Copyright © 2012 by John Doe
The questioner didn't ask what trademarks are, though, and so I'll not go into that here.
Answer 2: If the question is how do you make your computer PRINT a circle-R, that would depend on the computer and what software you're running. However, one standard keying system allows you to hold the ALT key and type on the numeric pad to create special symbols. The Circle-R would be Alt-0174, or on a laptop perhaps FN-0174. Most PCs also have a character map from which you can cut and paste any available symbol.
Answer 3:
On the Mac, simply hold down the "Option" key and type the letter "r." The Mac operating system uses hot keys for many common typographical symbols:
Option r: ®
Option g: ©
Option 2: ™
It is a capital letter "R" contained within a circle.
The symbol that means 'registered' is a ®.
Typing (r) should autocorrect to the registered trademark symbol.
Registered Nurse....
The symbol capital R within a circle [®], or circled capital letter R, is the registered trademark symbol. This indicates that the product is registered with a national trademark office (ex: Registered, U.S. Patent and Trademark Office). If a trademark is not officially registered, then it will be marked with a superscript TM (in capitals).
Symbol for "registered trademark"
The registered trademark symbol, an R in a circle, indicates the preceding logo, slogan, etc. has been formally registered; the trademark symbol, a superscript TM, indicates the mark has not been formally registered.
You can put a trademark symbol on your product before it is registered. However, it isn't backed by anything official and it could be copied or imitated.
The ® symbol can be used after a business name that has been registered as a trademark.
Facebook is a registered trademark, which earns it the right to use the ® symbol.
The law doesn't specify.
How much do registered nurses make a week?
In MS-Word, you can type (r). It should automatically be converted to the "registered trademark" symbol, by Word's autocorrect feature. You can also use the "Insert Symbol" command - or, if you use Windows, open the CharMap application, find the symbol, then use copy & paste.