There are basically two types of CDs.One is a write only and the other is a read write CD.With the write only CD, it does exactly that.You put the data on it once, and use it as often as you like.BUT you can put no more data on that disk.
With the read write CD it theoretically works like a floppy disk.In practice from my experience it is significantly less reliable.The computer must be capable of putting the data on the CD in the read write format.
If you are buying a new computer it will probable come with a CD drive that can put the data on a CD and then read it as often as you like.
In the long run it may be more cost effective for you to buy the new computer, and make the CD's on that computer.
If you buy new or try to update an old computer, you may want to consider either memory sticks that work in the USP port of the computer, or an external drive for back ups. They are essentially electronic floppies.
Memory sticks are cheap.You can get a 8gb stick for less that $10 a 32gb for about $20.Each of these will hold 1000's of times more date than your floppy. (Most floppies contain 1kb or less)
While there are those who safely use the memory sticks, I prefer the external hard drives.Again these are cheap about a $100 dollars for a 1tb drive.You can put every thing on the drive that is on your computer, dozens of times and still have room left over.
While you are using floppies today, if you decide to start scanning your source document, the large capacity drives will be appreciated.By scanning your source document, you can easily have several copies of those valuabledocuments.
Remember an Electronic copy of a document is just one that has not been printed to paper yet, It contains the same information as the paper copy but is easier to read as you can zoom to make it larger.