Which action/filter can i use for a Member Plugin [closed]

You could try this:

function restricted_access() {
    if( ! is_user_logged_in() ) {
        global $wp_query;
        $wp_query->set_404();
        status_header(404);
    }
}
add_action( 'wp', 'restricted_access' );

By default, always, if the user is not logged in it will give them the 404 page. The following two functions will keep non-admins out of your Admin Panel and will also hide the black admin bar from the front-end.

function redirect_nonadmins(){
    if ( ! current_user_can( 'administrator' ) ){
        wp_redirect( site_url() );
        exit;       
    }
}
add_action( 'admin_init', 'redirect_nonadmins' );

function no_adminbar() { 
    if( ! current_user_can( 'administrator' ) ) {
        add_filter( 'show_admin_bar', '__return_false' );
    }
}
add_action( 'after_setup_theme', 'no_adminbar' );

Edit – Some explaination

The function is_user_logged_in() returns a true / false boolean; True if the user viewing the current page is logged in. False if the user viewing the current page is not logged in.

The function current_user_can() will check the current users capabilities. In the above I check if the current user has administrator capabilities. If not – do not allow them to view the admin panel and do not show the black admin bar on the front end.