Data from Form to custom module page


I am using drupal 8.

I have a custom module page that show data from database. I also have added on custom form to this module page. Now I want to know, how to alter the content of the webpage based on the values submitted in the form by a user.

In sort, I want to know how to use the values submitted to form to in a controller method to alter the data on the module page.

Please help……….

Drupal version: