Docker-jitsi-meet customization

Hello, Sorry if I asked stupid questions, I’m new to docker but I’m eager to learn.
I have successfully setup docker-jitsi-meet on my VM. If I customize or make changes to docker files using “docker exec -it xxxxx bash”,

  1. Will the changes persistent? Or are they gonna overwritten whenever updates available?
  2. How to make it persistent?
  3. How to update?

Any help would be greatly appreciated. Thank you!