How to organize an entrance to one Wordpress site using an account from another?

Question

WordPress

The situation is this:
There are two sites, main and child .
On the child site, when authorizing / registering, I want to make a button like "Login using the main ".
How to implement something like this? Are there plugins available?

Answer 1

Use the same database for both sites, but with different prefixes.
You will have to write the login form yourself and request authorization data from the user table of the main site.