To make the water stop flowing from a faucet, you "turn it off". Use "turn off" instead of other words like "shut", "stop", or "close".

You also "turn off" these things:

• the lights
• the TV
• the heat
• the oven
• your (cell) phone
• the engine (of a car)

"Turn off" is a phrasal verb. Like a lot of phrasal verbs, the object can come afterward like this:

Turn off the faucet.

And it can also come between "turn" and "off":

Turn the faucet off.

But "it", "them", and "that" have to come in the middle. They sound weird at the end:

Turn it off.