I’ve used this plugin for adding custom fields in WooCommerce.
https://ww.wp.xz.cn/plugins/wc-fields-factory/
ok and it work`s for what i need?? you see the custom fields in the invoice ?
Give it a try or ask in its support area.
i’ll try for product ,it’s ok , but what i need is for customer ,more exactly i added two fields in shiping adrees and i want to show them in invoice but i don`t know how , it’s important for company because we have customers company’s and wee need to show on the invoice the name of the company the registration number etc. and for registration number woo don’t have a field
I recommend asking at https://ww.wp.xz.cn/support/plugin/woocommerce#new-post so the plugin’s / theme’s developers and support community can help you with this.