@nswuser007 The USB extended storage support was first introduced with HEN v1.7 (still works with v1.8)
Plug in a USB drive.
Go to Settings > Devices > USB Storage Devices
Select your USB Device.
Select 'Format as Extended Storage'
You can now run/install/move games on the USB extended storage drive.
Make sure you use at least Hen v1.7 (v1.8 works fine too) when using extended storage.
You can even plug the USB drive into another PS4 console that is running Hen v1.7/v1.8 and use the same installed games from the USB drive.
(make sure to run Hen first if sharing the USB drive!)