Are you trying to send a list of documents or are you trying to receive a list of documents?
If you are attempting to send a list of documents, the other server will dictate the allowed content, and you will not be able to send a list unless that server allows it.
If you are attempting to receive a list of documents, you require either a POST or a PUT endpoint. Documents can either be send as its binary or as a base64 string. Either way, you would require an import mapping. If you receive the list as a base64 string, you would have to decode it in a loop.
you can merge all your documents and create a new document and send the new document to REST API