You can invite members and guest to your space. You can also assign specific roles to space members.
Space is not charged for inviting guests. Guests can see (Read only) projects and its tickets they are invited to. They can also comment on tasks and add bookmarks to the project. Guests can also see timesheets and total logged hours but can not see project ETA and timeline.
Members can see and update tickets of projects they are invited to. They can also log hours and see timesheets and total logged hours for projects they are invited to.
Manager have access to all projects and they are able to change project priorities. They can also change some of the Space settings like Workflows and Members. They are also able to invite new members to the space.
Admins have access to more space settings like Space profile and Billing. Admins can also invite other admins and change roles of existing users. Admins will also have access to financial data in future.
Members can be invited via Space settings and can also be invited while assigning the task to a member.
Guests can be only invited from the project detail page by using Sharing options.