Service technicians are expected to have a Field user account on Cloud. You will need to invite them by email.
To add an account for the technician:
1/ Go to “Account > User & Permissions” in Settings.
2/ Scroll down, and you will see an area for Field users. Click “Invite field users" and invite the technician(s).
Check out this article for more details.
Once added, the technicians will be added to your existing pool of installers and other Field users. They will be available in the Scheduling Assistant when you schedule service calls.
