Certificate of Mailing  
You can prove you sent it with Certificate of Mailing.
When you need to verify that you’ve sent a letter or package - purchase a Certificate of Mailing.

A Certificate of Mailing is a receipt that provides evidence of the date that your mail was presented to the Postal Service™ for mailing. It can only be purchased at the time of mailing. And don’t lose it! It’s the only official record available.

Learn about detailed Features and Fees for Certificate of Mailing.
 
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You use Certificate of Mailing with:

First-Class Mail® – Letters, envelopes, and small packages weighing 13 ounces or less.
Standard Mail - Items weighing less than 16 ounces can be sent at discounted presorted and automation rates.
Package Services - Send small and large packages, envelopes, and tubes. includes Parcel Post®, Media Mail, Bound Printed Matter (paid by permit imprint only), and Library Mail.

You can combine Certificate of Mailing with the following Extra Services:

Special Handling - Provides preferential handling for fragile or perishable items.
Parcel Airlift Service (PAL) – You can have your package sent by air to or from a military base outside the 48 contiguous states.

Related Publications

Domestic Mail Manual – Read our Quick Guide to Mailing within the U.S.
Certificate of Mailing, Domestic Mail Manual