A lot of the times both "zipcode" and "state" are mandatory fields.

Zipcode is easy, the platform likely wants my postal code.

You have to be a little bit more creative with state, sometimes "We don't have any states" is fun to see printed on your address label on a parcel, other times "Denmark" could be considered a state in the EU and that can be an answer, but most times "N/A" is enough.