We want to add customer address at the first step, but we can not find the column for customer address in your template, As we are having 500+ customers so it is not possible for us to add one by one.
You have to first create the customers, address separate using data import. The address form is the separate form and it’s not part of the customer, therefore you can not make customer and address simultaneously using data import.
If you’re adding customers manually in the account, then in the popup you will get option to add customer basic details along with address