Team members have access to any project shared across the team, while guests only see the projects that they have been invited to.
Team roles determine which projects the teammates who share your teams have access to. You can see who is a Member or Guest in the team by clicking "People and Teams" in your organization dropdown.
Guest users will display a grey guest badge in the top corner of their card within the team.
Clicking a user icon will move you to a new popover page where you can add or remove projects the guest has access to, upgrade them to a "Member" in the team or remove them from the team entirely.
To add them to more projects in the team, simply click the "Add [name] to another team" and start typing the name of the project and a list of suggested results will appear. Click on the project name to add it to the list.
Upgrading a team "guest" to a team "member" will give the user access to any shared projects (private/invite-only project will still require an invite). To do so, click the "Change to General Member" link at the bottom of the popover. You'll be asked to confirm the change; click "Yes, I'm sure" to go forward with the upgrade or click "No, cancel" to return to the popover window.
You can also remove a guest entirely from the team here. To do so, click the "Remove [name] from all projects in the team" link at the bottom of the popover. This opens a right-hand panel where, you'll be asked to confirm the removal. If the user has any open tasks in the projects you'll be asked to either complete them or reassign them to another team member. When you're ready, click "Remove [name]" to complete the process.
Clicking the user's name will open a right-side panel where you can view all the teams they have access to and quickly jump to view their tasks in each. This option is available with team guests as well.
Please note that you can upgrade guests to members, but you cannot downgrade members to guests. You can learn more about inviting guests to your team here.