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Home > Guides > How shipping labels work
A shipping label is prepaid postage plus routing data printed on one page. The barcode tells the carrier what service you bought, where the package is going, and how much it weighs. Every scan of that barcode updates tracking: origin scan confirms drop-off, intermediate scans mark transit, and the delivery scan closes the loop.
| Part of the label | What it does |
|---|---|
| Barcode (and the tracking number under it) | Unique ID for your parcel; every scan logs against it |
| Service marking (e.g. Xpresspost) | Tells handlers which speed and handling rules apply |
| Destination address | Where the parcel goes; also printed in text for humans |
| Return address | Where it comes back if undeliverable |
| Weight | What you declared; used for postage accounting |
| Ship date | The date the postage is valid from |
Everything the carrier's computers need: the tracking number, the service level, the origin and destination postal codes, and the declared weight. The tracking number is assigned when the label is purchased, which is why you can have a tracking number for a parcel that hasn't moved yet: the number exists before the first scan.
One thing people get wrong: the label is single-use. Printing the same PDF twice and sticking it on two parcels is postage fraud, not a clever hack. The second parcel travels on the first parcel's dime, and carriers flag duplicate tracking numbers.
| Scan event | What actually happened |
|---|---|
| Label created / information received | The label was bought; the carrier knows a parcel is coming |
| Origin scan / acceptance | The carrier physically has your parcel |
| In transit / processed at facility | It passed through a sorting hub |
| Out for delivery | It's on the truck for the final leg |
| Delivered | Handed over or left at the address |
| Exception | Something needs attention: address issue, customs hold, weather delay |
The gap most people misunderstand: "in transit" scans only happen when the parcel passes a scanner. A parcel can travel for days between scans without anything being wrong. No scan doesn't mean no movement.
A torn, smudged, or low-ink barcode forces a manual key-in of the tracking number, which slows the parcel and can lose tracking events. Print the label with fresh ink or toner, keep it flat on one face of the box (never wrapped around an edge), and don't cover the barcode with tape: tape glare defeats scanners.
You can get a Canada Post Xpresspost label by asking your AI assistant: per-label quote, you approve the exact price, one-time payment, and the label PDF is provided. Canada-only, flat-rate Xpresspost, 5 kg max. Print the PDF anywhere and drop the parcel off.
Ready to ship it? Get a shipping label with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and get your label.
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