How do I fill in the identifying doc ID metadata?

This is the identifier uniquely and permanently associated with the electronic document in the Document Management System where it was created and managed, in order to enable identification. It can be, for example, the SAP identifier, the ERP identifier, the SdI identifier, the technical ID of the Protocol, a unique number, or, failing that, the file name (if unique). In addition to the identifier, the hash imprint of the document being preserved and the corresponding algorithm (default: SHA-256) must also be indicated among the metadata elements. This imprint is a string of numbers and letters resulting from a mathematical algorithm applied to the bits that make up the document, which is essential for proving the integrity of the document itself over time.