reduce the force acting between the 2 surfaces

reduce the roughness of the 2 surfaces coming in contact

use wax, grease or oil

all of the above are ways of reducing friction

Brakes used on a bike

Tires from a car on the road

Tread on the bottom of your shoes

All are examples that are helpful

Pencil marking on paper

Engine parts wearing out

sand placed on ice in the winter

Using an eraser to erase marks