You want to pass the data collected in one filed to another field in the same form. For example, if you want to display the users Name from the First Name field in an HTML field or in a read only field throughout the form to make it more personal.
How To Fix It
Out of the box Gravity Forms does not support using merge tags in form fields. By default, merge tags are not available until after the form is submitted and the entry is created.
There are a couple third party plugins that will add support for using merge tags in form fields before the form is submitted.
Disclaimer: The Merge Tags in HTML Fields plugin, has not been updated in 2+ years (at the time of this writing), but I have tested it and it still works.
Need More Help?
If you still need help, feel free to use the comments or chat options below.