You didn't say what screen you are referring to, so this answer is in general.
A foreign address doesn't use a zip code. It uses a postal code. You have to first tell TurboTax that the "type" of address is a "foreign country address", and then the input fields will change and have a box for "postal code."
Look higher up on that screen for "type of address", and in the dropdown menu associated with that box choose "foreign."
