I just purchased a HooToo external flash disk and am trying to use it to transfer files between my desktop and iPad. So far my iPad is not recognizing the external drive. Not certain if I formatted incorrectly or am using the wrong app on my iPad or .... what?
iPad Pro 11-inch Wi-Fi
Connection of external storage devices is possible - with some caveats...
To be recognised by iPadOS, the attached USB storage device must be formatted to FAT, FAT32, exFAT or APFS with a single partition. As the iPad has limited power capabilities, dependent upon the Storage Device, an external power source is often required.
If your iPad Pro has a Lightning port, you will need to use an Apple Lightning to USB3 Camera Adapter to directly connect USB devices to the iPad. This adapter has both a USB 3.0 Type-A connector and an additional Lightning port to supply power, from your iPad Power Adapter, to both the iPad and connected device. The Power Adapter must be rated at 12W or more.
If you have one of the newest iPad Pro models, with a USB-C connector, you may need to utilise a powered USB hub (i.e., it has its own source of power) - connecting both the iPad Pro and the storage device to ports on the hub.
Some additional information can be found here:
Connect external devices or servers with Files on iPhone - Apple Support
https://www.imore.com/how-use-external-hard-drives-your-iphone-or-ipad
I hope this information proves to be helpful in resolving your difficulties.
Using HooToo (external disk) with iPad
