How do I make the block fall when player touch it?

does anyone know how to make a block that if the player touches the block will fall?

Use "Player On collision with Block" event.

How do you make the block fall depends on what behaviors are you using. It can be Bullet, Platform, Physics, MoveTo, Tween etc.

For example, with MoveTo you can do this:

Block Move to x=Self.x, y=(Self.y+1000)