Provides you to add a custom attribute for a customer. which will be displayed on the customer registration page, customer account page and checkout shipping page, and so on. You can manage that customer attributes from the backend.
Create an unlimited number of customer attributes. Create an unlimited number of customer address attributes. Place customer attributes on the front end or backend. Display on specific pages such as registration, checkout, and many more. Admin can edit the customer attributes. Admin users can set default values for the customer attributes. Admin users can add attributes of type text, text area, date, yes/no, multiple select, and dropdown.
For more Detail click here Customer Attributes Extension