It seems like such a little thing, but unless you know how Zen Cart works, making the telephone number not required without disabling it completely can be like finding a needle in a haystack.
Firstly, why is important? Well, unless you are shipping with a courier that requires a telephone number, having this extra field in your registration page can deter some customers that want to give out as little personal information. They see the red star (meaning the field is required) next to the telephone field and they quickly abandon their carts, leaving you scratching your head while watching the who’s online page. But, you can’t just remove that red star or PHP will return a warning that the telephone number field is required.
So, here’s what you do:
Next, open /includes/languages/english.php (this file may also be in your overrides folder), and find:
and change to:
And that’s it! Now your customers won’t have to provide their telephone number and you’ll still be able to gather this information from the rest of your customers.