post
https://platform.staging.brexapps.com/v1/referrals//document_upload
The url will be a pre-signed S3 URL to upload the referral doc securely. This URL can only be used for a PUT operation and expires 30 minutes after its creation. Once your upload is complete, we will use this to prefill the application.
Refer to these docs on how to upload to this presigned S3 URL. We highly recommend using one of AWS SDKs if they're available for your language to upload these files.