I purchased a 2TB External HD online but it says it is an EXFAT drive. What should I do to format it for my 2019 iMac?

Hi nbob651,

To format for Mac, use Disk Utility

1. Go to Disk Utility (Finder > Go > Utilities > Disk Utility)
2. In Disk Utility, select "View" in the toolbar, then "Show All Devices."
3. Select the main drive in the "External" Section. This is NOT indented. Its name will end in Media.
4. Click Erase
5. Use a name, use APFS, and GUID Partition Map.
6. Click Erase

Hope this helps!

Cheers,

Jack

Depends on what you're going to use it for. If you want to be able to boot from it, then reformat it as APFS. If it's only going to be used to store data, then HFS+ (Mac OS Extended) is better. Especially for a hard drive rather than an SSD.

If you want to use it for both, you can use Disk Utility to split it into physical partitions. Format one partition as APFS so you can install another instance of Big Sur on it, and the other as HFS+ for data.