Thank you! Sorry for the late reply o.o
When you draw a line it spawns a prefab with a line renderer. That prefab also has a child of a Edge Collider 2D. In the line script, i set the values of the size index (in the positions tab of the line renderer) to where the mouse is , so i just have to get those values and set it on the edge collider 2D as well. And then i just set the tag or layer as ground so the player can walk on it. im not very good at explaining things, but i hope it makes sense.