What does “my sound” mean?

I always hear people talking about how most of your sound comes from YOU and not the horn or the mpc/reed combo, (not to say those don’t have any effect of course), but what do you guys mean by that exactly? Are you talking about embouchure? If so, is there anything I should experiment with, or just kinda figure it out on my own?

For background information (if needed) I’ve been playing in middle/high school for about 6 years now. I got a Jody Jazz HR maybe two or three years ago; it works great, and it’s what I usually play on, but that’s about all the experience I have with other mps. I feel like my sound is fine, but I want to sound as professional as I can. So what’s gonna help me out the most here?