What external hard drive device should I get to back up my 2020 MacBook Air?

Apple provides a guide here.

I have an iMac as my primary Mac and I use a powered drive which is always connected to the computer. Notebook users need something a bit more portable; the rest of my family has notebooks and I've provided them with the USB drives similar to those in the Apple Store. These a small drives, about the size of your hand, with a USB cable and rely on the computer to give them power to function. They work just as well as my powered drive.

Just be aware that an off the shelf drive of any sort will probably be formatted for Windows and a good option is to reformat it for Macintosh.

sblehert Said:

"What external hard drive device should I get to back up my 2020 MacBook Air?"

-------

Hard Drive Specs:

Get a Solid State Drive (SSD), as it has a faster DTR (Data Transfer Rate). Be certain that the original packaging reads Mac compatible - particularly one for your current macOS. Some have the ability backup both simultaneously.

Formatting It:

Though not necessary, consider formatting it for reliable use. Use Disk Utility to format it as APFS type.

1. Go to: Applications Folder
2. Open: Utilities Folder
3. Select: Disk Utility