Every lens (well, almost every. Only a very very very few exotic ones cannot I believe.) can focus to infinity. Either use the distance markings on the lens, switch to manual focus, and twist the focusing ring to the infinity mark. Or if there's no distance markings, switch to manual focus and twist the focusing ring such that the front element of the lens is the nearest to the camera, i.e. the lens is at it's shortest.
But infinity is actually slightly before the extreme end of the focusing ring turn. But at small apertures it should not matter as much.
Lazy way: find a distant object, as in really distant, yet well lighted and good contrast. Auto-focus on it.
