Add a Customer Attribute

1. Go to Customers in the main navigation bar on the left-hand side. 
2. Press Customer Attributes on the upper right-hand side. 
3. Press + New Customer Attribute on the upper right-hand side of the screen. 
4. In the pop-up window, input the Attribute Code and Attribute Name
5. Select the customer attribute type from the drop-down menu. This can be a STRING (a combination of letters, numbers, and symbols) or a sequence of NUMBERs
6. Select how the custom field will appear under Frontend Input Type
7. Choose Text, TextArea, Select, Date, DateTime, or a File.
8. Press Save Changes.