How to make a slope?

Hi I’ve been trying to make a slope for my 2d platfromering game. I have tried by using a plane and tilting it 45 degrees but since it’s a plane on a 2d game it won’t show up. So instead I tried to make a triangle in blender and use that as a prefab.

I am kind of new to Unity so if what I said doesn’t make sense just tell me what you don’t understand and I will try to clarify.

What do I export the blender object as? and what can i do to make it a prefab?

Just use a primitive cube object in Unity for a slope. Simple.