On an Android smartphone, pressing the Home button will bring you back to the home screen. This function is mandatory for all Android smartphone.
The secondary command of the Home button
It is still possible to change the secondary command (activate voice control, get a preview of the current app) of the Home button.
The secondary command can be either triggered by making a long press or double tapping on the home button.
It will all depend on the version of Android installed on your smartphone, as well as its model.
You can also configure the secondary command of the home button to trigger applications such as Nova Launcher Prime or Apex launcher.
These "launchers" provide a customizable and efficient replacement for your Homescreen.