When creating your sales and purchase rebates, you’ll need to have "No. series" setup for both. The "No. Series" page is the main page within Business Central that defines the document codes to be used on all documents created within the system. We advise to create a separate one for Sales and Purchases so that they are stamped individually, not only for audit purposes but also for clarity. Each of these will require a Starting No, Description and a tick whether these will be Default Nos. or Manual No’s. Default numbers will auto-generate a number using the Starting No. you defined. Manual numbers will allow for an alternative number to be used, which can be keyed in by the User. 

Using the example below, as you start posting rebates, your Last No. Used will continuously populate with the last document number used on a sales/purchase rebate. An Ending No. can be defined if you wish to stop the numbering sequence at a specific number when using Default Nos.. Leaving this blank will enable the "No. Series" to continue posting until all the numbers available to use based on the length of the Starting No. have been used up.