External Drives for Mac. Back up fails

I have a new My Passport for Mac. I was assured that it did not need formatting. It will not back up. I use MacBook Pro OS X 13.2 High Sierra.
I attempted to re-format and got as far as Erase: Name: Format - where I found 4 versions of APFS preceding the existing format. Which do I use? I then see Scheme: with 3 choices. Which?
Can you advise, please.
I tried phoning (Australia) and couldn’t spare the time in the queue.
Many thanks

If you want to use APFS just use the option APFS. Once formatted with this file system IIRC it will only work on Mac OS High Sierra machines. If you are using it for time machine you can also use Mac OS extended journaled. This will work with any Mac machine.