I'm very sorry I have no idea what the first thing you said was, is the water okay? How do I get pure water? How do I make it higher?
All water is OK, though it is not suited to all fish. I gave you some fish species (in very general terms) that should be OK if you use the water you have.
Making water harder means adding more dissolved calcium and magnesium (these two minerals are the prime minerals that determine the GH). This however will significantly limit the suitable fish. You can use a calcareous sand substrate, which is a sand composed of minerals that slowly dissolves calcium and magnesium. There are also rift lake cichlid mineral salts. But this means mixing the water outside the tank at each water change. This may not sound like much, but having done it, I can attest that it is. Making the water soft goes the opposite direction, except here there is only one option and that is using "pure" water on its own or mixed with the tap. Pure water means distilled water or Reverse Osmosis water. Rainwater is basically pure water, though these days it may pick up "stuff" as it falls and not be so "pure." You can buy distilled and RO water, or use a RO unit. They are not inexpensive, and again you have to prepare the water outside the aquarium.