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A certified mail receipt has two parts: the mailing receipt you keep (with the 22-digit article number that powers tracking), and the return receipt (the green card or its electronic equivalent) that comes back with the recipient's signature and delivery date. Together they prove you mailed the letter and that it was delivered. Keep both with your records.
The article number is the 22-digit tracking number assigned to your certified letter: it's the single most important thing on the receipt. You'll find it printed on the white mailing receipt the post office gives you at the counter (and on the green certified mail label itself, above the barcode). Every tracking lookup runs through this number: photograph it the moment you get the receipt, because losing it means losing online tracking.
The number also encodes the service type: type the full 22 digits into USPS tracking and the system recognizes it as a certified item, showing the certified-specific events.
The return receipt (PS Form 3811, the green card) is the proof-of-delivery half. When you mail certified with return receipt service, you fill out the front of the card with the recipient's name and address, and the card travels attached to your letter. After delivery, the carrier fills in the back and it's mailed back to you. Here's what the fields mean:
| Field | What it tells you |
|---|---|
| Article number | Matches your mailing receipt: confirms this card belongs to your letter |
| Signature (front of card) | Who signed for the letter: the addressee or an authorized agent |
| "Addressee" vs "Agent" checkbox | Whether the signer was the recipient themselves or someone authorized to receive mail for them |
| Date of delivery | The date the letter was delivered and signed for |
| Delivery address (if different) | Filled in when the letter was delivered somewhere other than the address on the card |
| Your name and address (back of card) | Pre-printed by you at mailing time so the card finds its way back |
Between mailing and delivery, the article number shows a trail of scan events. The ones that matter:
One thing people misunderstand: "refused" is not the same as "never sent." Courts and contracts often treat a refused certified letter as delivered for notice purposes: the recipient can't dodge a deadline by declining to sign. That's exactly why people pay for certified mail instead of hoping regular mail suffices.
You have a choice at mailing time. The traditional green card comes back to you by mail with a physical signature: slower, but some courts and old-school contracts specifically want the paper card. The electronic return receipt delivers the signature image and delivery data online, usually faster and cheaper. If a contract or court rule says "return receipt requested," either satisfies it unless the rule specifies the paper card.
The whole point of certified mail is evidence, and evidence you can't find is evidence you don't have. Staple the mailing receipt to your copy of the letter the day you mail it, and file the green card with them when it comes back. If a dispute arises months later: a tenant claiming they never got the notice, a client disputing a deadline: the article number lets you pull the full tracking history, and the signed card ends the argument. Keep the set for at least as long as the underlying matter could come back to bite you; for leases, contracts, and legal notices, that usually means years, not weeks.
If you send a letter through LetterAgent with the registered option (US Certified Mail or Canada Registered Mail), you don't handle any of the paper yourself: there's no counter visit and no physical green card to file. The tracking status for your letter is available through your assistant: ask it for the job's status any time and it can report where the letter is and whether it's been delivered. The same statuses above apply, and the delivery record serves the same proof-of-delivery purpose as the card.
Ready to mail it? Send your letter with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it's printed and mailed.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
Need help? Ask your assistant: it can check a job's status any time. If it ever can't handle something: hello@getletteragent.com