Import WordPress login credentials

How can I add a function to implement external login credentials like WordPress credentials or social media logins?
I would like to access my wordpress database to import the login credentials.
This will be an improvement, because my customers has to register only once.

There is an OAuth plugin.

ok, and how can i handle this feature with wordpress?
i already installed the OAuth2 Plugin on kanboard (probably this will be the client), now it seems i need a “server” on wordpress side?

Can you help me please?

I don’t know much about wordpress, so, I can’t help you with any details. Check this out.

This appears to be the source for it.