Changes to labels don’t appear

Let me answer your questions one by one.

>> Not sure what I’m missing but if I change “State” to required, it still appears on the screen as “State (optional).

The required property of the State field will change according to the country selected.

You can use the below hook in your child theme’s functions.php to make the state field required for all the country.

add_filter('thwcfd_address_field_override_required','__return_true');

>> Also, if I change the label for the second address field to “Address 2”, no label appears at all.

We are not able to recreate the issue that you have mentioned. We are able to add/show a label for the field billing_address_2 on the checkout page.

Could you please raise a ticket through our website. We hope our technical team will be able to help you.

Thank you!