iPad Air, how to format external disk?

Yes - contrary to information posted by Phil0124, it is possible to format external storage devices using an iPad running iPadOS 18 and later.

Simply connect your external USB storage via an appropriate USB-C hub or Adapter*. Using the Files App, identify the external storage device from sidebar - then touch-and-hold the associated device icon to the Action Menu:

From the menu, select Erase:

* e.g. Apple USB-C Digital AV Multiport Adapter

USB-C Digital AV Multiport Adapter - Apple

You cannot format a drive form an iPad at all.

You will need to connect it to a computer to format it.

Once it's formatted, you can use a USB-C hub or dock to connect more than one device to the iPad at a time.

LotusPilot wrote:

Yes - contrary to information posted by Phil0124, it is possible to format external storage devices using an iPad running iPadOS 18 and later.

Simply connect your external USB storage via an appropriate USB-C hub or Adapter*. Using the Files App, identify the external storage device from sidebar - then touch-and-hold the associated device icon to the Action Menu:

https://discussions.apple.com/content/attachment/7a70f366-d172-4078-904b-691f6f392725

From the menu, select Erase:

https://discussions.apple.com/content/attachment/af065ebd-156b-4705-b213-bd1ac6f195cc

* e.g. Apple USB-C Digital AV Multiport Adapter

USB-C Digital AV Multiport Adapter - Apple

That's new. I was totally not aware of that. Good to know.

If you cannot format the SSD drive using your iPad, or independently using a Mac or Windows PC, this would suggest that the drive is either defective - or that the drive requires attention using a suitable disk utility to set/reset the partition table (MBR or GPT) prior to formatting.

Not particularly new. This capability was introduced with release of iOS/iPadOS 18.