The difference between get and got is how they are going to be used. Get is known to be the present tense form of the word which means that if you say “get,” you may be about to acquire something or you are describing how someone has acquired something.
When you say “got,” this means that you are already done getting the object or the idea that you were supposed to get. The English language can be highly confusing for a lot of people but as long as you will study it, you will begin to understand how the terms can be used properly.
The phrase 'get it' on its own would typically only be used as either an imperative or a question. For example, 'I get it' means, 'I understand.' Get it means that the speaker realizes something. Putting the word, got in place of get could mean that the speaker has something, is receiving something, or has a situation under control.
Get it or got it alone could mean either a realization or enlightenment. To get could also expect to receive. Got and get are both interchangeable with have or have to. Got to could also mean must. For example, 'I got to go now' could even say, 'I have to go now.'