After you file

Your W-2 is the document you received from your employer that shows how much you earned and how much was withheld from your pay for taxes and Social Security, etc.  The Form 1040 is your tax return.  ?The 1040 is what you prepare and file with the IRS to request your tax refund.

What does your letter from the IRS say?  There is a letter number or CP number in the top corner.  What is that?
And what tax year is the letter about?
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**