The default setting for Annotation on a shared screen is set to allow. This feature option can be valuable when your participants are collaborating on your shared content. However, it can also be disruptive if an participant has access to the annotation tools, but is not aware of their impact on the meeting.
You have the option to decide if and when you want participants to annotate on your shared screens.
Change your default option for all scheduled meetings by signing into your account on the
website portal. Once you have signed in, navigate to 'Meeting Settings' on the left, then scroll down to 'In Meeting (Basic)'. The toggle button is gray when disabled for all meetings, or click to enable for all meetings and the button is blue. Whatever you choose, the setting applies to all meetings you schedule.