Where is the application form file in Drupal php?

Question

Drupal

I need a file that works out when applying. So that I insert my code for sending a notification to telegram there. What is this file?

Answer 1

There is no such file. In Drupal, you need to intercept the event in your module.
First you need to create your own module and make a hook in it that can pick up your event.
The name of the hook is key in this process. Dig here.
If the form is submitted by the webform module then look for the hooks of that module.
If I'm wrong somewhere, please correct me.