Username field in contacts list - what is the purpose?

[Shan]

Which ‘username’ field are you talking about? Can you share a screenshot?

If you are talking about the ’ name ’ field then you can set it during registration by passing the first name & last name parameters under the contactInfo variable

wixUsers.register(email, password, {
    contactInfo: {
        "firstName": 'James',
        "lastName": 'Bund'
    }
});