Outputting form values into another html

Hi,
I’m quite new to all these please guide me along thanks!

Lets say i created a form in a html.
The form contains 2 text fields for user to enter their first and last name. It also contains a submit button.

When the user click the submit button, how do i output the user first and last name which they have entered into action.html.
Saying something like your first name is *****
Your last name is *****

What should the code in action.html be like?