Reset a WordPress user password via FTP
wp_set_password( string $password, int $user_id )
Update the user’s password with a new encrypted one.
With known user ID
wp_set_password('password', 1);
With known user login name (username)
$the_user = get_user_by('login', 'Adam');
wp_set_password('password', $the_user->ID);
Reset a WordPress user password via MySQL
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