Admins can enable the In Review setting, allowing Technician Users to mark their work as In Review when they finish. The Completed status isn't available on the work order form. Admin or Limited Admin users should review work orders marked as In Review and can either send them back to a technician or mark them as Completed.
See the gif and read the steps below for the In Review setting.
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Guide
Admins select the Admin Settings module from the main menu.
Select Manager Modules tab.
Under the Settings section, select Work Orders configuration.
Toggle on In Review or toggle off if you want Technician users to mark work orders Completed.
Hit the Save button to keep any changes.
With this setting, Technician Users don't see the Completed status on work orders.