what information is required in proof of arrangement between your brand and the third-party manufacturer

I am the registered owner of the trademark, and my products are manufactured exclusively by a third-party manufacturer under my brand. During the Brand Registry application process, I was asked to upload proof of the arrangement between my brand and the third-party manufacturer.

I would like to know specifically what information is required to be included in the "proof of arrangement." While the help links provided mention uploading proof, they do not detail what specific elements or documentation should be included to meet this requirement.

To avoid further delays, could you please provide clear guidance on the exact documentation or details that need to be included in this proof of arrangement?

Your clarification on this matter would be greatly appreciated, as this is my fourth attempt to resolve this issue, and previous responses have not provided the specific guidance needed.