Everything I'm reading shows that in order for an application to use onedrive, it has to do the oauth2 thing to get credentials. But what if you're a batch process and don't have a web interface for your users.
Google's API has a special type of account called a service account where once you set it up, you can control access to everything from that one account, no need to interact with users. Does such a thing exist for onedrive?
App-only authentication doesn't require the user be prompted for credentials but it also isn't supported in 100% of scenarios. For example, the APIs need a user principle for creating special folders and resolving a user's personal site. Also, it is only supported for OneDrive for Business, not Consumer. Consumer always requires the user be prompted for initial authentication.
Another option would be to spin up a web service of some sort that handles initial user authentication, ie. a sign up page. With that, you can retrieve a refresh token for offline authentication and store it for the user. Every authentication from then on can be done using the refresh tokens, which doesn't require a user prompt.