If you need to submit periodic VAT returns , you must submit the annual statement of taxable customers (also referred to as ‘customer listing’) via Intervat .
Exception: if you have been authorized to file your periodic returns on paper, you may also submit your customer listing on paper.
If your company is subject to a different arrangement, you can submit your customer listing through Intervat . Paper submission is allowed, but in this case you must request the form from your authorized office and return it completed to the scanning center.
How can you easily submit your customer listing through Intervat?
If you have ceased your activity , you must submit your customer listing within three months of losing your VAT taxable status.
What should I do if I have not performed any actions that should be included in the customer listing?
Source: financien.belgium.be