1. Don’t ignore the letter.  Most IRS Letters are simply asking for information.  The letter will deal with a specific issue and will give you specific instructions.  Responding to the letter with the information required should resolve your issue.
2. If the letter indicates a changed or corrected tax return, review the information and compare it with your original return.
3. If you disagree with the information in the letter, mail a letter to the IRS and explain why you disagree.  The address to mail the letter is on the contact stub at the bottom of the notice. Be sure to include information and documents for the IRS to consider and allow at least 30 days for a response.
4. Usually, there is no need to call the IRS for most notices.  If you need to call, use the phone number in the upper right-hand corner of the notice.  You will need to have a copy of the tax return and the notice when calling.
5. Always keep copies of any notices received with tax records.
6. Be alert for tax scams. The IRS sends letters and notices by mail. IRS does not contact people by email or social media to ask for personal or financial information. The IRS will not demand payment a certain way, such as prepaid debit or credit card. Taxpayers have several payment options for taxes owed.

Information from IRS Tax Tip 2017-49