Team members are users with access to a job. If you want a user to see a job include them as a team member by clicking the Edit button. Team members can also be included from departments outside your own. This is useful when you require assistance on a job from someone outside of your normal team or department or if they are a stakeholder in the job.
You can add team members by default by including them in the the Job Defaults in the Settings Window under the Company Tab. Click Add and select the Team Members to include. New jobs will now include the default team.