How to attach the COI as the default attachment during registration for supplier to sign & reattach?

Summary:

Is there any way to attach the COI as the default attachment during registration, so that the supplier can download, sign, and reattach in business classification?

Content (please ensure you mask any confidential information):

During supplier registration, buyer wants supplier to sign the COI and attach it to the business classification (to track expiry). For this, buyer must provide the COI document to be signed by supplier during registration.

Is there any way to attach the COI as the default attachment during registration, so that the supplier can download, sign, and reattach in business classification?

One way of doing this is to create a mandatory question with the required attachment, however, the attachment will not be part of the business classification to track the expiry.