Instructions for recovering a Microsoft password can be found here:
https://support.microsoft.com/en-us/account-billing/reset-a-forgotten-microsoft-account-password-eff4f067-5042-c1a3-fe72-b04d60556c37
If you simply want to type a letter and print it out, you just need a word processing program. You've already got a very basic one on your computer, called WordPad. To find it, click on the Start button and scroll down the list of programs until you get to Windows Accessories. Click on it and you'll find WordPad listed within the submenu that appears.
However most people prefer to use something a bit less basic. The most popular freebies here seem to be OpenOffice Writer (which, unsurprisingly, is part of the full OpenOffice suite of programs)
https://www.openoffice.org
and the equivalent program (also called Writer) from the LibreOffice suite
https://www.libreoffice.org