Typically, when you receive a letter from the IRS in the mail, they will either provide instructions for your next steps, or they will simply be informing you that additional time is needed to process your tax return. If your letter has instructions and a date to reply by, you should follow the requests of the IRS by the requested date. If your letter does not request any further action on your part for the moment, you simply need to wait until they are done with their review.
Please see the following links for more information on what to do if you hear from the IRS:
I got a letter or notice from the IRS
What to Do if You Get an IRS notice
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"