function merge_affiliate_name( $update_data, $user_id, $contact_id, $form_id ) {

    if ( isset( $_COOKIE['affwp_ref'] ) ) {

        $affiliate = affwp_get_affiliate( $_COOKIE['affwp_ref'] );

        $userdata = get_userdata( $affiliate->user_id );

        $update_data['Field Name'] = $userdata->first_name . ' ' . $userdata->last_name;

    }

    return $update_data;

}

add_filter( 'wpf_forms_pre_submission', 'merge_affiliate_name', 10, 4 );

function merge_affiliate_tags( $apply_tags, $user_id, $contact_id ) {

    if ( isset( $_COOKIE['affwp_ref'] ) ) {

        $apply_tags[] = 'Affiliate Tag';

    } else {

        $apply_tags[] = 'Not Affiliate';

    }

    return $apply_tags;

}

add_filter( 'wpf_forms_apply_tags', 'merge_affiliate_tags', 10, 3 );