A rename policy for devices can be set at the following places:
When adding a placeholder device. For more information, see Adding a Placeholder Device.
The Automated Device Enrollment (formerly DEP) Profile
Enrollment settings, managed under Organization > Settings
Note: It is possible to use payload variables when renaming devices. For more information, see Payload Variables. Renaming your devices to a static payload variable (for example, %CompanyName%) will result in the devices being named the same with an added number. For example, TestCompany, TestCompany (1), TestCompany (2), etc.