This depends entirely on the context. If you just completed a project that you were excited about with a group of people and completed it successfully and on time, you might say loudly "We did it!", which is the same as saying "We accomplished it! Good for us!" Of course, if somebody was asking you who did something (bad or good) and you did it with a group of others, you would also say "Yes, we did it." You might not be as excited, though.

We did it! = We were successful.

We did it - verb.simple past tense of do. (more than one person accomplishing something together.) Ex: > We did it John! We beat them by 20 points. (someone expressing how great themselves and one other person did.) >We won the game! We did it! (team chanting)... (a whole team expressing how great they did/accomplished.)

We did it! = 'We managed to do it!' or 'We succeeded in doing it!'

It expresses accomplishment, success and/or completing a task. You'll often hear the saying when a project is completed or when a sports team wins a game. Say you and your friend worked really hard on a project and finally completed it. You may say, "We did it! We're done!" As a group of friends, you finished the project. So as a group, everyone takes credit. We did it can also be a confession haha, like kids who broke something may eventually confess "we did it, we broke it" lol.