When I give "apply as the shape key" it seems that it only takes a part of the cloth simulation, I want it to take the whole simulation, my cloth simulation has 200 frames and it seems that in the shape key it has only 20
If you do "Apply as Shape Key" it will create a snapshot of the vertex positions from where you are on the timeline as save that as a shape key. The shape key have no animation data. It interpolates from the base shape key to the cloth shape key linearly. That is, if you place the Value on the Cloth shape key on 0.5, each vertex point will be in between the Base and the Cloth.