function custom_apply_tags() {

    // Don't run if WPF isn't active

    if ( ! function_exists( 'wp_fusion' ) ) {
        return;
    }

    if ( isset( $_POST['plan_id'] ) && $_POST['plan_id'] == 'OutdoorBodyMembership' ) {

        wp_fusion()->user->apply_tags( array( 'Outdoor Body Membership' ) );

    } elseif ( isset( $_POST['plan_id'] ) && $_POST['plan_id'] == 'Elite' ) {

        wp_fusion()->user->apply_tags( array( 'Elite Membership' ) );

    }


}

add_action( 'init', 'custom_apply_tags' );