Roles determine what a person can see or do in a project. Tasks overview has a table of roles and tasks.
Here is an overview of roles:
The roles of Administrator, Translator, Consultant/Reviewer and Observer come from Paratext and come into effect when they log in to Scripture Forge with their Paratext account. They follow the permissions that Paratext gives for these roles and can only be changed in Paratext.
Administrator (of a project) - Administrator tasks overview lists the things they can do.
Translator - Translate tasks overview lists the things they can do.
Consultant/Reviewer - People with these roles can only look at the translated texts, questions, answers and likes. But they can insert notes, view note threads, edit and delete their own notes
Observer - People with this role can only look at translated texts, questions, answers and likes, and note threads.
These are Scripture Forge roles. Typically, people who are invited do not have existing roles in the Paratext project.
So, they will have one of these roles.
Commenter - People with this role can view texts, add comments, view threads, edit and delete their own comments. These people have access to the Translate view, but not the Community Checking view.
Community Checker - People with this role can answer questions and comment on answers. Community Checking tasks overview lists the things they can do.
Viewer - People with this role can only look at the translated texts and comments in text. Viewers cannot see the Community Checking view.
Scripture Forge comments are the comments created in Scripture Forge. Any notes created in Paratext are only visible to users with Paratext roles.
Share - if enabled, you can invite people to share in the task of community checking or to just look at translated texts and some related activity.
These people must accept their invitation to be activated with user credentials (password and so on).
Users has a filter so you can filter users by role. It also has the Share with others control.
https://paratext.org/paratext-training/tutorials/project-sharing/#roles