Passwords can't be removed from Webex meetings. To bypass a password requirement, your personal meeting room (PMR) can be used. The PMR link is a standing link, so anyone with the link can access a meeting. To prevent users who are not invited from joining the meeting, lock your meeting after all invited participants have joined:
https://help.webex.com/en-us/article/vjfafi/Lock-or-unlock-your-Webex-meeting
