After you file

Did you print it out?  It should say on the instruction page or look it up here……
<a rel="nofollow" target="_blank" href="https://www.irs.gov/uac/where-to-file-paper-tax-returns-with-or-without-a-payment">https://www.irs.g...>

When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s.  Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS received the return.