Gravity Perks Copy Cat AddOn
This plugin allows you to copy values from one field to another within the same form. Values can be copied either automatically as they are typed or when a specific Checkbox in the form is checked.
For example, with automatic copying the user can enter their first and last name into a field, and those values will be immediately copied into the Name input on a Credit Card field as they type.
Copying with a Checkbox is particularly useful for situations like specifying a billing and shipping address. There is a good chance the user would desire to enter the same address for both fields. You can configure a Checkbox to copy the user-entered values from the billing address field to the shipping address field.
Copy Cat supports copying to and from almost all Gravity Forms fields, so the possibilities are endless!