Question about Raspberry Pi Camera Module v2 8MP

No, this camera has a fixed focus, i.e. the lens is fixed to the sensor. With these tiny dimensions (similar to the camera in a smartphone) this is not a problem, as the depth of field is very large due to the system and is always sufficient for the applications of this camera.
Greetings, Paul

Yes, the focussing distance can be adjusted by turning the knurled ring on the lens. To make this easy, the camera module usually comes with a white plastic cylinder with a matching hole in the centre (diameter approx. 2 cm, height approx. 5 mm).