It can be used a lot here are some examples ^_^ "i lost my phone" "is this it?" "yes thats it!" "which shop is it?" "thats it!" Generally the term is used for stating you have found or seen or recognised something you were looking for. It could be also used for remembering something for example "who sung this song?" "beyonce!" "thats it!" It can also be used for encouragement when somebody did something right or well For example if you answered a question correctly someone could say "thats it, well done!" ^_^ hope i helped you!

"That's it" is normally used in three different ways. If I ask someone a question and they give me the right answer, I might say, "that's it!", meaning "you are right!". "That's it" can also be used to identify something you are looking for. "Upon finding the murder weapon, the detective said, 'that's it'." Another usage can be when something is finished or no longer possible. If I am playing a game of chess and I have the opportunity to put my opponent in checkmate, I might say, "that's it! Checkmate!" I was once riding in a car with a friend in a rainstorm. The car began to aquaplane (the tires left the pavement and skimmed across the top of the water on the road because of our speed) and my friend said, "that's it!". He meant that he no longer had control of the car. Fortunately for us, he released the accelerator and the tires once again came into contact with the pavement so he could regain control.

used to say that something has ended. Well, that's it, we've finished - we can go home now. That's it! I'm not putting up with any more of her rudeness.