Click the "Display name *" field, and enter a prompt for your user. In this example, we are asking for a full name. 

We can now select If this  field is "Required", or if we want to "disable" it without deleting existing DATA 

Select the field type for your user input field

(Select an HTML input type)
Text field
Larger text area
Dropdown list
Radio button list
Checkbox

Select the field type for you user input field

Click the "Placeholder text" field and enter the text that will appear as a placeholder.

If a text field type has been used, you can select a validation option from this dropdown

(No validation)
Boolean: value will be either true or false
Date: value will be a valid date
Email: value will be a valid email address
Numerical: value will be a number
URL: value will be a valid http or https URL

Text fields can also have a "Maximum length" field value

When configured click the "Create" button to complete adding this field

Create a custom registration field