If a user can't see all available locations in the Location Management section, it's likely those locations haven't been assigned to them. To grant access, follow these steps:
Assign location access to an employee
From the left-hand menu bar, click People.
Click Employees.
Find, then click on the user.
Click the Locations tab, then click Add/Edit Locations.
From the Choose Selection Type drop-down select All Locations.
Tick the locations to add, then click Save.