How to get rid of Google Now? I have a Moto G4 plus, and I don't see a way to Deactivate the Google app in my home screen (far-left screen).

I have the last Android update installed.

Also, it would be great if I also could get rid of the Google search bar (in order to use duck duck go, for example).
That might be apart of your launcher. If it's not you'll have to  be rooted because the app is a system app. But, removing it can cause problems such as bootloops so be very careful.