How can they remove video card from motherboard?

You can't exchange integrated video between motherboards. It is soldered onto the board and removing it would almost certainly not only be exceptionally difficult, but also almost defintiely damage the IGP anyway. Beyond that, it is highly unlikely that it would work in another board even if you had the tools and the skills to connect it to another board and that's assuming that it can even be put on your other board, an unlikely scenario. If graphics is not integrated, then it is a discrete card that can simply be pulled out of a slot, unlike the pretty much immovable integrated on-board graphics.

Moving on to laptop parts, this is all even more difficult or even impossible. Heck, laptop graphics cards are often only compatible with one or a few laptops and can't be connected to most other laptops. Integrated on-board graphics is no easier to manage than the desktop examples in the paragraph above either.

Long story made short, you almost definitely can't use the graphics from a laptop in another laptop under almost any circumstances except for replacing the entire motherboard and maybe other components as well and even that is often not possible because motherboards must be especially made to fit in a specific chassis.