formatting

Rank amateur question:

iTunes formats CDs as I need them. How do I format a CD to back up a Quicken file?

You don't. Just pop in a blank disc, create a new burn folder, drop in the file and click burn (more info on burn folders here).

For CD's you get ONE chance to write to them. So when you backup that Quicken file to CD, it formats and writes at the same time. Then you cannot write to that CD again.

For the purists: Yes, CD-RW can supposedly be reused, but who uses them?

Unless you are sure this file should be written to a disc for permanent, unalterable storage, I'd suggest a thumb drive instead. Files that are likely to change periodically (like Quicken files) are best backed up in a way that they can be re-written if needed, so a thumb drive or cloud storage is generally the best way to go.

If this was a file that is unlikely to ever need writing to again, such as "2006 budget" or something like that, then of course burning to a disc will work fine.