How friction affects motion?

Friction is a very helpful thing and with out it you couldn't move, speed up, slow down, change direction, bend, or twist. Without friction nothing would ever happen. Friction can oppose motion or it can make it difficult for an object to move across a surface. Friction both helps an hinders every thing we do.
the object would not move without friction
The friction acts in the opposite direction to that of direction of motion.
So friction slows the object and if no external force is applied the object will come to stop.
Friction is a force that opposes the direction of motion between two materials. It is parallel to the surface your object is touching. Friction depends on the coefficient of friction and the normal force (force exerted perpendicular to the surface your object is on; opposes gravity on a flat surface). There are two kinds of friction: static and kinetic. Static friction must be overcome in order to move an object. Once the object is in motion the friction acting on it is called kinetic. Static friction has a threshold of force that is needed to get the object moving but once the object is in motion it can be moved at a constant velocity with less force required.