Is there a way to add a third-party app's users to People app as a contact method?

Question

Like the Facebook integration but anyone can do it, I'm only asking because I can't find any API on it (not a good sign)

Answer 1

You will have to access the user's Contact and once you update the Contact list then it should show in People app.

https://learn.microsoft.com/en-us/uwp/api/windows.applicationmodel.contacts.contact

Hope this helps.