Add Supplementary Functionality to React Webapp

I have an existing React webapp that is functional and styled the way I want it. I would like some modifications done to add some functionality: After clicking submit on this basic web form and sending the payload to my backend API, I want the user to be presented with a popup dialogue box with an input field that invites them to enter their email address to receive some supplementary information after their interaction is complete. When the user enters their email and clicks submit, this information needs to be sent to a backend REST endpoint in a particular format. I would also like a button aside or below the submit button that says something like "Skip providing email" which simply closes the dialogue and displays the thank you message that is already built in. Automated bids will be downvoted and hidden. To prove you're not a bot, include your favorite food in your bid. Must be fluent in English.