If you'd like to prevent visitors to your room from adding content from the toolbar (GIFs/Stickers, Media Players, Whiteboards, Games, etc.), you can do so in the settings. To disable, head to the "Room Details" tab in settings and scroll until you see Permissions. It looks like this:
Then toggle the Add Content button off if you'd like to prevent guests from adding content. The button will then appear grayed out and, from the guests' point of view, their toolbar will be disabled. To turn Add Content back on, all you have to do is toggle the button again (making it appear purple). This will enable visitors to add content to the room. You will also be prompted to enable or disable this permission when you first make your room public.