By default, there is no built-in option to disable admin notification after user registration. You can use the following function code. Please see the steps below:

Note: Make sure to have a complete site backup before proceeding

    1. Navigate to WordPress dashboard - Appearance - Theme Editor.

    2. Under Select theme to edit, choose (BuddyBoss Child/whatever theme is active), then click Select.

    3. Below Theme Files, select Theme Functions (functions.php).

    4. Append the code just before the closing PHP tag “?>”:

remove_action( 'register_new_user', 'wp_send_new_user_notifications' );
remove_action( 'edit_user_created_user', 'wp_send_new_user_notifications', 10 );
add_action( 'register_new_user', 'bb_wp_send_new_user_notifications', 10, 2 );
add_action( 'edit_user_created_user', 'bb_wp_send_new_user_notifications', 10, 2 );
function bb_wp_send_new_user_notifications( $user_id, $notify = 'user' ) {
switch($notify) {
case 'admin':
$notify = 'none';
break;
case 'both':
$notify = 'user';
break;
}
wp_new_user_notification($user_id, null, $notify);
}

Note: Any modifications are considered custom work already. Know more about our Support Policy here: https://www.buddyboss.com/support-policy/