Managing Stock Levels

Try to paste the following function into your theme’s functions.php file.

add_filter('woocommerce_get_availability', 'my_availability_message', 10, 2);
function my_availability_message($args, $product){

	$args = array(
		'availability' => __('Always Available', 'textdomain'),
		'class' => 'always-available'
	);

	return $args;

}

You should need to adjust the “Always Available” string to meet your need.