Hi @enghnai
If you are scheduling your meetings in advance, you can un-check the Waiting Room option during meeting setup.
If you are starting your meetings instantly, you can click on the Security icon in the meeting and un-check Waiting Room.
If you want to disable Waiting Room for good, then you can do that here: https://zoom.us/profile/setting
But you will still need to have at least one security measure in place on your Meetings - so you are left with Passcode or Require Authentication.
Hope this helps.
Rupert