If gravity could be manipulated what would be affected? like friction, time and motion?

Oh, but there is friction in deep space; wherever two surfaces come together, moving or not, there is friction as long as there is a force between the two. That force need not come from gravity forces however. Any force will do it. When an astronaut pushes off on the bulkhead of the ISS, there is friction between her hands and the bulkhead. And the force of gravity had nothing to do with it.

Gravity affects the rate of time, but that's only observable when looking in from outside that gravity field. That is, anyone on planet Earth would not see any change in the rate of time, but someone looking back from the Moon, as it comes crashing in toward the now stronger pull of Earth would see that rate change. BTW, the Moon would close in, whether it actually crashes or goes into a closer, faster orbit depends on too many factors to predict here.

Of course, everyone on planet Earth would need to go on an immediate crash diet as they would gain in weight as soon as the gravity force increased. And if that increase is too much, everyone would be morbidly obese, get pinned down to the surface, and die.

Interestingly, because that increase affects both the water and the swimmer, a swimmer's flotation would not be affected. If she floated in normal gravity, she'd float in the extreme gravity. See the source for the math if you're into that sort of thing.