How much do you use attack move?

I have been playing this game for a long time and I really enjoy playing ADC. The other day my friend told me about attack move, and I have never used this mechanic because I do not know if it is used by any pros and I do not know if I understand how to use it.

I tested attack move out for the past couple days and I have mixed feelings about it. I certainly think it is good. But is this mechanic used often? To my understanding attack move is enabled by pressing x or a and then clicking an area near your intended target, and it will try to hit champions. I found the attack move to be set on x and a to not fit me, so I set it to spacebar.

How do most people use attack move and what key is attack move usually set on? Keep in mind this mechanic is really new to me and any online videos I seen with this seen to confuse me more, so im hoping that seeing it explained in text will help.