Any person you share files with in LookAt and that is not part of your team is considered a guest.
Setting a default project roles for guests means that the role you choose will be automatically given to any guest you share a project or a file with. You can always change this role for any user per project in the project settings menu.
There are two possible project roles you can assign to guests:
Reviewer - can view files, view comments made by others and also to add new comments.
View only - can view files, but cannot view comments made by others, nor to add new comments.
Setting a default project role for guests
1. Enter the team & users tab in the settings page
2. Hover over the Guest default role space
3. Click the pencil icon
4. Choose the default project role you wish to grant to your guests
5. Click save to finalize the action and to save the new default project role.