// add custom fields
function add_custom_fields(){
add_meta_box(
‘product_cf’,
‘Product Details’, //title
‘add_product_details’, //callback function
‘products’, //custom post type
‘normal’, //priority
‘low’, //where to show
);
}
function add_product_details(){
echo ‘this is a custom fields’;
}
//call the hook
add_action(‘admin_init’,‘add_custom_fields’);