Ax – D365FO – Number sequences

Number sequences are used to generate readable, unique identifiers for master data records and transaction records that require identifiers. A master data record or transaction record that requires an identifier is referred to as a reference.

Before you can create new records for a reference, you must set up a number sequence and associate it with the reference

See this Microdoft user guideline :

• Number sequences overview : https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/fin-ops/organization-administration/number-sequence-overview
• Set up number sequences on an individual basis : https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/fin-ops/organization-administration/tasks/set-up-number-sequences-individual-basis?toc=/dynamics365/retail/toc.json
• Set up number sequences using a wizard : https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/fin-ops/organization-administration/tasks/set-up-number-sequences-wizard?toc=/dynamics365/retail/toc.json