I usually use "delivery confirmation" when I send a package.
It costs $0.80 and can be obtained with Priority Mail and a Package - if the package is large enough!
I wanted to mail a 10x13 envelope that had a nicely folded piece of fabric in it that was nice and flat - and approximately 1/4 inch thick - and was told that if I wanted to get the "Delivery Confirmation" on that envelope, it had to go via Priority Mail! It wasn't a "package" because it wasn't thick enough.
So I opened the envelope, folded the fabric inside, and the Post Office clerk retaped the cut end. THEN I could get the "Delivery Confirmation" service and still send it via First Class mail.
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