@alissaleschke suggest sending the package so that it is tracked and signed for at the IRS. that way you have confirmation they have receiver it. Then prepare for a LONG wait. Best estimates are that since the IRS is so woefully backlogged and they generally process in the order received, it'll take 6-9 months for your return to be processed. It won't be visible on the WMR tool until they begin processing it, but with that post office receipt you will have peice of mind that the IRS has it.
