Filter for users on custom post type

Check this code

do_action('user_register', $user_id);
add_action ('user_register', "test");
function test($user_id) {
    $user = new WP_User($user_id);
    $role_of_user = $user->roles[0];
    if($role_of_user == 'your role'){
        $my_post = array(
            'post_title'    => 'My post',
            'post_content'  => 'This is my post.',
            'post_status'   => 'publish',
            'post_author'   => $user_id
        );
        wp_insert_post( $my_post );
    }
}

It will create a post when a user of your defined role is create by admin i.e from backend.

For profile update i.e if user role is update from some other role to your defined role

add_action( 'profile_update', 'my_profile_update', 10, 2 );

Use profile_update action and rest of the code same.