The pre-qualification form is sent by the buyer for their vendors to submit their details in accordance with their procurement policy and governance requirements. The form will need to be submitted on a regular basis (3 years or 6 months depending on vendor), and the buyer requests for you to submit the details via the system to help them keep track and perform their vendor assessment.
Here's a guide on how to submit a supplier form sent to you:
https://blog.tenderboard.biz/2020/08/26/tenderboard-supplier-forms/