The Multisite User Management plugin does that: https://wordpress.org/plugins/multisite-user-management/
Relative custom coding solutions/functions examples:
https://codex.wordpress.org/Function_Reference/add_user_to_blog
https://wordpress.org/support/topic/one-user-registration-for-multiple-sites?replies=5
- This reply was modified 1 day, 3 hours ago by AITpro Admin.
- This reply was modified 1 day, 3 hours ago by AITpro Admin.