Add checkbox to product type option in Woocommerce backend product edit pages
The answer is very simple… you just forgot to add a key id for your array in the first function, like:
$product_type_options['evisa'] = array( // … …So in your code:
add_filter( 'product_type_options', 'add_e_visa_product_option' );function add_e_visa_product_option( $product_type_options ) { $product_type_options['evisa'] = array( 'id' => '_evisa', 'wrapper_class' => 'show_if_simple show_if_variable', 'label' => __( 'eVisa', 'woocommerce' ), 'description' => __( '', 'woocommerce' ), 'default' => 'no' ); return $product_type_options;}add_action( 'woocommerce_process_product_meta_simple', 'save_evisa_option_fields' );add_action( 'woocommerce_process_product_meta_variable', 'save_evisa_option_fields' );function save_evisa_option_fields( $post_id ) { $is_e_visa = isset( $_POST['_evisa'] ) ? 'yes' : 'no'; update_post_meta( $post_id, '_evisa', $is_e_visa );}Code goes in function.php file of your active child theme (or active theme). Tested and works.
