User authentication from different devices?

Question

PHP

And so, we present the question:
A certain Vasya Pupkin opened an account on our website, then this Vasya decided to visit the site from the phone or being with a friend through his browser, but that's not a problem, when he comes home and opens his browser and Vasya has to re-enter our site login and password from the account, and later, lying on the couch, Vasya again has to enter the same data, but again on the mobile.
The question arises: How to be in this situation and save the login and password on both devices without additional manipulations with entering the site?

Answer 1

You create a table where the authentication key (cookies) is stored and each cookie is indicated to whom it belongs.
There extra. you can add additional info, cookie for which browser, etc. (purely for informing the user)
In general, that's the whole logic.
The user logged in to the site through the computer.
he signed up in cookies.
I logged in on the phone, the old key is not overwritten, but a new one is added.
Further, in the settings / user profile, he can choose which device will disable him