In one sentenceA long code the invoicing system generates for each e-invoice that never repeats, to distinguish it from all others when it is sent to the FATOORA platform.
Simply put
The sequential invoice number you see may repeat between two branches or two systems, but the unique identifier does not repeat anywhere.
The system generates it automatically and the user does not type it, and it is sent with the invoice in the second phase.
Example
Two branches of a pharmacy chain each issued an invoice numbered 1001 on the same day: the two numbers are identical, but each invoice has a different unique identifier that distinguishes it on the FATOORA platform.
Don't confuse it with
Invoice hash chainThe unique identifier distinguishes the invoice, while its hash proves its content has not changed and links it to the one before.