What this tool does, and what it cannot do
Labelbench does not issue tracking numbers, does not buy postage and has no connection to any carrier. The reference barcode printed on a label here is for your own sorting, and no carrier can scan it. If you have a real tracking number, it came from whoever you bought the shipping from, and this page is a shortcut to their tracking screen rather than a source of delivery information in its own right.
Reading a tracking number before you look it up
Cross-border postal items use a format set by the Universal Postal Union: two letters, nine digits, then two more letters. Those last two are the country code of the post office that accepted the parcel, so RR123456789GB started in the United Kingdom and LZ876543210FR started in France. The two letters at the front say what kind of service it was, with R for registered mail and E for express. Courier numbers follow no shared standard, which is why a UPS number starting 1Z looks nothing like a twelve-digit FedEx one.
Where to find the number
It is on the receipt from the post office counter, in the confirmation email from the shop you ordered from, or in the account area of whoever you bought the postage from. A number usually takes a few hours to appear in a carrier system after the parcel is accepted, and cross-border items often show nothing at all until they clear the first customs point.