Request and response is a workflow path
When a user clicks a button, submits a form, changes a status, or assigns an owner, the screen is asking the software to do something. That ask is the beginning of a request cycle.
The response is what comes back after the software handles the action. The response might confirm that a request was created, show that a field needs attention, update a status, or return the user to a useful screen.
You do not need to memorize protocol details to use request and response thinking. In business tools, the key question is simple: what did the user ask for, what changed, and how did the screen explain the result?
A request begins with a user action and should end with understandable feedback.