I have my Admin Console set to notify me when users attempt to access their accounts from devices. For example, if a teacher tries to sign into their account on a personal computer, an email alert is sent to me. The alert takes me to Devices > Mobile & endpoints > Device Approvals. I can then block that device or approve it. This option will provide specific details regarding the account and device details. I review the details and then use the serial number, as needed, to add the device to our company-owned inventory. Devices can be added to the company-owned inventory via CSV file too.