When migrating to Autonomous Database (ADB), three supported options include RMAN Cross-Platform backup and restore, PDB unplug/plug operation, and Datapump export/import. RMAN Cross-Platform backup and restore allow for a platform-independent backup and restoration process. The PDB unplug/plug operation enables the moving of a pluggable database from on-premises to the cloud. Datapump export/import is a widely used Oracle utility for high-speed movement of data and metadata between databases. These methods ensure a smooth and efficient migration to ADB.