When attempting to add a Worker to a Service File via the Add link in the Workers section, their name is not appearing when searched for in the Worker field.
The Worker may need to have the Case Service that the Service File was created for added to the Assigned Services section on the Clinical Tab on their Worker Profile, and/or have Accepting New Clients set to Yes on the same tab.
To edit the Accepting New Clients setting, select Edit to the top right of the page, check the corresponding checkbox and save.
To add a Case Service to the Assigned Services section, select edit to the top right of the section, check the checkbox next to the necessary Case Service and save.
The user attempting to add the Worker may also have "Limit Access to other workers to current worker's own site tree" enabled in their Security Class and is attempting to add a Worker who is not assigned to the same Site Tree.