How to automatically generate a path?

Question

Yii

How can it be implemented so that when switching to the controller without specifying any parameters, a certain path is formed!
For example, when the user enters into the command line http://user/index?id=or http://user/index?the path was automatically formed http://user/index?id=mainpage&user=1
. By what means is this implemented?

Answer 1

Does the user need a path in the address bar?
Default values ​​in Yii2 are very easy to implement

public function actionIndex($id="mainpage", $user=1){
    // ...
}