To add an NIF/NIPC field to your checkout page, you can use a plugin like Brazilian Market on WooCommerce, which includes an NIF field. Once installed and activated, this plugin will automatically add the field to your checkout page.
Alternatively, you can use the Checkout Field Editor plugin. After installing and activating it, navigate to WooCommerce > Checkout fields. You can add a new field and name it NIF/NIPC.
I hope this helps! If you have any other questions, feel free to ask.
To move the NIF/NIPC field after the email field, you will need to change the priority of the field in the Checkout Field Editor. The lower the number, the higher up the field will show. So, you can set the priority of the NIF/NIPC field to a number lower than the email field.
As for adding more descriptive text in the bank transfer area, you can do this by going to WooCommerce > Settings > Payments > Direct Bank Transfer. Here, you can add more descriptions in the “Instructions” field. More info: https://woocommerce.com/document/bacs/
I hope this helps! If you have any other questions, feel free to ask.