I have a application consisting both UI and Service Exe's that saves critical data files from users machine to his Onedrive Cloud space. My application handles the Authentication using Microsoft Graph and gets the required Access token / Refresh Token by allowing the user to entering his credentials .
Now I have this prospective customer who may have above 500 users. He says the O365 logins are integrated with his Domain's Active Directory and the passwords change every 15 days. It is not possible for user to enter all these passwords every 15 days.
Please advice what I should use, there are loads of documentation on Microsoft website and I am unable to pin on anything specific.
I have a free microsoft developer account. Will I need to convert it to paid one ?