Connecting to OAuth 2.0 authentication might be a common and critical task to do for many developers, especially in Microsoft Office 365 environment. It could be a connection to OneDrive, Excel, SharePoint, OneNote, even the big developer platform such as Microsoft Graph. It could be connecting to any other cloud app services such as twitter, facebook, google, pinterest, or any other cloud services in this world.
You can take a look to find out how we deal with Microsoft OAuth 2.0 authorization code is retrieved and how the flow works for you at: https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-v2-protocols-oauth-code.
In practical way, you can follow my step-by-step below if you find the article is not clear enough or lack of examples. This article will be focusing on Microsoft Online credential which can be used with Azure Active Directory or Microsoft Online account.
Registering Your App
Before you can make connection to any cloud services using OAuth 2.0, you would need 2 things, Client ID and Client Secret. Anything that connects using OAuth 2.0 is considered an app, and you need to register that before proceeding. This will usually generates you a Client ID and commonly with Client Secret, which acts same like your own username and password.
