If the application is installed in a windows platform:
Agent based and agent less scanning will work fine for scanning Windows machines. For scanning Linux and MAC workstations we use network scan and we reach the client machine through Telnet or SSH. For sanning network devices, we use SNMP.
If the application is installed in a non-windows server:
Agent based and agent less scans for scanning windows workstations do not work. As a workaround, you can install a remote Asset explorer on a windows machine and sync the information back to ServiceDesk Plus – MSP server. To know more about remote asset explorer, refer here. Kindly open the link and navigate to Configurations -> Discovery -> Distributed Asset Scan to know more. For Linux, MAC and network devices, you can use network scan.