External hard drive and iPad

Yes you can. While this link doesn't tell all the drives you can use it does give you some information --> Connect external devices or servers with Files on iPad - Apple Support

If you want to see loads of advice on this, go to YouTube and search for videos about external drives for iPad Pro. If you go with something like a SSD drive, you'll need a powered hub. You can use simple thumb drives without a powered hub if you don't think you'll be moving lots of data back and forth.

Hello,

iPadOS 13 supports the following disk formats with a GUID partition scheme:

• macOS Extended journaled — YES Read and Write
• APFS - NO
• FAT32 — SOME*
• exFAT — SOME**
• NTFS — NO

*iPadOS 13 supports solid state devices formatted as FAT32 such as a SD card. iPadOS 13 does not supports mechanical hard disks formatted as FAT32.

** iPadOS 13 supports disks formatted as exFAT as long as it was formatted with Disk Utility on a Macintosh. The disk cannot be formatted by Windows.