How to add custom fields
To add custom fields you must have the "Custom Fields" addon.
Accessing the custom fields editor
To access the custom fields editor, navigate to Users -> Profile fields into your WordPress dashboard. You will now see a table with the default fields that looks like this:
Adding new fields
With the custom fields addon enabled, 2 new sections are now available on the left side of the fields table. The "basic fields" and "advanced fields" sections are now visible.
Each section contains the fields types that you can add. To add a field simply click it's button. For example, to add a text field, simply click the "Text" button within the "basic fields" section. The field will be created and you'll be redirected to it's editing page, where you can customize name, description, requirements and other settings. Each field has it's own settings.