Simple Question!!! What is the IRS mailing address for tax forms????
Go to this IRS website for the address to mail a paper tax return, with or without a payment, by state - https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment
The answer is also simple: It depends on where you live and whether or not you are sending a check to them or are expecting a refund.
Please see this IRS webpage for your answer.