Superscore? Is it true?

Hi, I’m junior and I have some questions.
So, I heard some Universities can send all SAT or ACT scores that we took and looking for only highest grade for each section. For example, If i got a (Reading&writing: 500 / math: 600) at first SAT and (Reading&Writing: 600 / math: 550) at second time, they will add the high scores which is 600 for reading&writing and 600 for math?
Is it right? I wanna go to University of North Texas and I’m going to take a SAT soon and it’s not my first time so I want to know what is the real answer and I want to know what does “Superscore” means exactly.

Schools vary from best single sitting to super super scoring, meaning they’ll combine the best sections of SAT and ACT. North Texas is a Best Section school, meaning, they super score. You do have to take the writing. Depending on class rank, you may be offered automatic admission with certain SAT scores. It’s all outlined on their “will I get in?” link. Good luck.