This endpoint enables you to provide documentation (e.g. invoice) associated with a specific payment (via the payment UUID). This upload is not mandatory for a payment to be processed, though it helps streamline payment processing. Each document is limited to 5 MB in size (total of 15 MB per payment and can contain documents in the following formats: doc, docx, csv, jpg, jpeg, pdf, png, xls, xlsx, txt, odt, ods, heic, heif, gif.

Please note that the request has to be an array of files (an array of binary strings is not supported), and the header's "content-type" differs from other endpoints.