The resistance that one surface or object experiences when there is a relative motion with other surface is known as friction.
It is a very important force because one won't be able to halt moving items without friction. Friction also generates response force, which aids us in walking, writing, holding objects, and nailing nails to walls.
Friction prevents car tires from skidding on the road, hence driving vehicles on the road would be impossible without it. There is a slew of other things that can't be done without causing friction.