Why is my MeshCollider do not fit with my character ?

It looks like you have a very small scale on your character model, which you might want to address (what modelling program did you use to create it, and when importing it what scale did you choose - 0.01 or 1.0?).

But the simple solution to make your capsule collider fit more tightly is to adjust the centre, radius, and height values at the bottom right of the inspector pane.

Thanks a lot for your answers I managed to resize my capsule (a bit tired I did not pay attention to 0.00 ...) thanks again