gravity - what is gravitational force?

As a hobbyist, I'll give a limited answer.

Gravitational force is particle or wave?

Until we actually find out what gravity is, the safe answer here is that we don't know, but it's probably a wave and a particle. Most (perhaps all) fundamental particles in quantum physics are waves and particles. Light for example, Electrons too, though we might think of an electron as a particle, it's wave properties are easily demonstrated, and wave properties of protons can be demonstrated as well. There's a ton of stuff that can be googled on the wave-particle duality. Here's one.

It's unclear exactly what fundamental particles "are" so saying a fundamental particle is "this or that" is a bit iffy since we can't see them. We can only study how they behave. Gravity, if it's a fundamental particle, which it probably is, it should be both a wave and a particle, and a field. I know, that's a little hard to think about. We don't get to have many tangible answers in quantum physics.

I know that gravitation depend of the mass and the rotation speed

Gravity depends on mass. Period. Rotation speed can creates a centrifugal force opposing gravity and making things lighter, but that isn't gravity. The gravity is still 100% governed by mass.

what is the transmission medium of this wave the same like
transmission medium of the light ?

Light (as far as I know) doesn't require a transmission medium. Gravity shouldn't either. Sound waves require a medium but light and gravity can pass through empty space.

If you have more specific questions, you might have better luck on Physics rather than Astronomy. Also, my 2 cents, Stan Liou has made some intelligent comments well worth reading.