How can we trick an android device that the device does not get our real location? Is it possible to make the Android Operating System  receive false location data or not receive any data about our geolocation at all. And how we can do it in the  maximal clean way so that the third-party applications that are installed on the phone could't even suspect about it?
The phone has a GPS sensor and the OS can read the values from this sensor. Thus, the OS knows your real position.
However, the apps have no access to the direct OS reading - they can only ask the OS to give them the position. And the OS has builtin support to give them fake results.
To do that, do the following steps:

Enable developer mode (as described here).
In the developer mode, enable &quot;Allow mock locations&quot;. This allows for apps to override the GPS sensor input by a fake position provided by them.
Install any app with exactly this feature, like Fake GPS Location.

It works a little bit differently on some phones, for example on my Moto G8 there is no &quot;Allow mock locations&quot; option in the developer mode. In most cases, it is possible even on them, but a little bit differently.
Extension: apps can know if it you did these, but they have probably no way to know, if the actual position they've got is mocked. Probably it can be prevented only by rooting the phone. Thanks @Robert for the info.