This time of year, you might be asking yourself, "How should I mail my tax return?"
I'm not a lawyer, an accountant, a financial advisor, or a doctor, but this page at the IRS seems to support the idea that you should send your tax return certified return receipt via the US Post Office:
I used to always get a certificate of mailing because I once thought I heard that was what the IRS recognized, but the above page seems to suggest that might not be good enough if you need to prove you mailed it.
I found the above link here:
Here's someone who disagrees, in case you're looking for justification for just dropping it in the mail and not worrying about it: