Compression-what is it? When do we use it?

Do you have any videos explaining compression, how to do it and when to use it? Am I right to assume that compression is mostly for belting high notes? Also is there a search function for the forum? I hate to be asking questions that have already been answered 

Hi, Liza! Here's day 10 of my beginner course, which covers cord compression: https://www.30daysinger.com/tutorial/30-day-beginner-course-with-camille/10. For belting or other loud singing, our cord compression increases (more specifically, the vocal folds stay together for a bit longer each time they vibrate). But we always want a balanced, healthy level of vocal effort so that our cords compress the air beneath them, which creates energy in the sound wave. Insufficient cord compression (or closure) results in a weak, breathy sound with little energy. You may also enjoy this video, which demonstrates a few different types of onset: https://www.youtube.com/watch?v=HTNJt-EQyBA. 

Thank you 🙏 is there a search function anywhere on the site so I don't ask repeated questions that others asked already?

You're welcome, Liza! There isn't a search function yet, but we are working on it!