How do you make something a Convex Collider?

I want my meshes to collide with each other without being rigidbody. I guess the only way to do this is to make them convex right? I cant find out how to do this its not in the box collider settings. So basically where is the setting to make meshes convex?

Thanks

They still need to be rigidbodies. If meshes aren't convex, they simply won't collide at all, rigidbodies or not. There is no way to have collision without rigidbodies.

It's in the mesh collider settings.

See MeshCollider.convex.

If you apply such a collider through the editor you can find a tick box you can click.