functions.php

add_filter( 'woocommerce_product_tabs', 'woo_edit_tabs' );
function woo_edit_tabs( $tabs ) {
	
	// Adds the new tab
	
	$tabs['enquiry_form'] = array(
		'title' 	=> __( 'Ask a question', 'woocommerce' ),
		'priority' 	=> 50,
		'callback' 	=> 'woo_enquiry_form'
	);

	return $tabs;

}
function woo_enquiry_form() {
	echo '<h2>' . __( 'Do you have a question?', 'woocommerce' ) . '</h2>';
	echo '<p>' . __( 'Drop us a line by compiling the form below. We will be more than happy to reply to any of your questions!', 'woocommerce' ) . '</p>';
	echo do_shortcode( '[your_form_shortcode_here]' );
	
}