Alter The WooCommerce Onsale Text

function my_alter_sale_text() {
	return '<span class="onsale">'. __( 'MY CUSTOM TEXT', 'ocean' ) .'</span>';
}
add_filter( 'woocommerce_sale_flash', 'my_alter_sale_text', 20, 3 );

All PHP snippets should be added via a child theme's functions.php file.