Manual:$wgEmailAuthentication

Details
Set to true to enable email authentication: all email functions (except requesting a password reminder email) only work for authenticated (confirmed) email addresses.

On account creation or when users change their passwords or on request, a confirmation token (link) with a limited life time is mailed to that unconfirmed email address.

When the user returns with that token to the wiki, the email address is confirmed.

The confirmation status ("Your email address was authenticated on ") is always shown in the user email preferences.

It also enables the other email notification options.

If set to false then no email notifications are enabled for the entire wiki.