What is the most optimal solution for registration / authorization through social networks. networks?

Question

Social media

In addition to the standard login and registration on the site (login / password), the task of registering and logging in through social networks arose. As well as account bindings (this seems to be simpler).
Reviewed a bunch of sites, but everywhere there are some inconveniences. Some sites when authorizing through social. the network is asked to select a login again, enter an e-mail and a password, others do not ask for anything at all, but then in the settings you cannot enter a login, for example, and, accordingly, log in in the usual way (login / password), and not through social networks. network.
In general, tell me the guides on the most competent implementation of the task of registration and subsequent login through the social. networks.

Answer 1

Is it supposed to be a CMS or something self-written?
There are ready-made plugins for CMS.