How to translate fields with WPML
Advanced Product Fields for WooCommerce allows you to add option to your products in two ways: via the Edit Product screen or via WooCommerce → Product Fields. Depending on which one you chose, your translation efforts will be different
Translating field groups
To be able to translate product field groups, you need to set them as “translatable” in WPML. You can do that by going to WPML → Settings and scrolling to the Post Types Translation section. Find “Product Field Groups” and set it as translatable.

If you now go to WooCommerce → Product Fields and edit one of your field groups, you’ll notice a new “language” section on the right. Click the plus icon to translate the field group.

If you are using WPML’s translation editor, make sure it is turned off. Switch the toggle to OFF as seen below:

Translating product fields
To translate product fields added to a product via the Edit Product screen, you essentially need to translate the whole product. WPML has an extension and information on how to translate products here.