Papermerge DMS is used to store documents. Documents can originate from any source i.e. you can upload documents from your local hard drive, from remote email account, S3 object storage etc.
Actually Papermerge DMS does not care where documents are coming from. All Papermerge DMS does, it exposes a REST API for ingesting documents. Thus, from application point of view, the is one and only point of ingesting documents - it is the REST API.
From user’s point of view though, there are two ways to upload documents:
Uploading documents via user interface is straightforward:
Actually “user interface” is yet another REST API client, in other words, “user interface” is a separate application, also called frontend application, which uses REST API for uploading documents. If you are curious for more details have a look at papermerge.js which is repository of the frontend application.
Papermerge DMS exposes a well defined HTTP interface with HTTP body (payload) being in json format. This means that you can use any http client (e.g. curl) to interact with Papermerge DMS e.g. upload documents, create folders, assign tags, move documents to specific folder, trigger OCR.
In particular Nodes, Folders and Documents section explains how to use REST API to upload documents (also it goes into details of all necessary concepts like nodes, special folders etc).