CD-R are "recordable" and come as a blank disk on which you can "burn" your own information. Once data is written to the CD-R, it cannot be removed.

CD-R/W are "re-writable." You can reformat the disk to erase information that's been written to it, and it can be used again to write new data.

Either kind, but especially for "data files," can be "finaled" with or without closing. If the data is "finaled" without closing additional information can be added via a second "burn" or recording session, assuming that there's sufficient unused space on the disk. Once the disk is "closed" nothing more can be added to a CD-R, and reformatting (erasing all existing information) is required before a CD-R/W can be used again for new data.

You can buy "music CD-R" disks for recording music, or "data CD-R" disks for recording ordinary computer data and/or program files. The "music CD" version is usually a few cents more expensive per disk than "data CD-R" disks due to having a "royalty fee" paid by the manufacturer; but you actually can burn any kind of information to either kind of CD-R. If the only thing you're going to record is music, the music blanks may make some sense, but for ordinary use it's usual to just buy whichever is cheapest, which usually means using the "data CD-R" disks.

John