Active directory migration to Azure active directory quest tool

We are having a scenario were we one ADDS forest, multiple child domains and  tree domain. tree domain already syncing with azure ad since office 365 is deployed already in this case we need to migrate users and computer to azure ad using quest tool i.e active directory separation from the current forest to azure ad forest. migrating users and computers to azure ad and migrating server and application on premises ADDS. Its hybrid scenario please suggest right tool.