@carolyn-hartigan , there should be no penalties if your mail is stamped with 5/17/21 by the post-office or any delivery services like FedEx/UPS etc.
For mailing address , please see this page from the IRS --
https://www.irs.gov/filing/where-to-file-addresses-for-taxpayers-and-tax-professionals-filing-form-1...
Is there more I can do for you ?
