The standard "mastering" burner software is ISO burning. Converting UDF (packet writing) disks to be able to be read by any CD ROM is an ISO conversion.
What you will be able to do in creating a CD depends upon what software you have. If the software is older, you may not be able to do things like directly create an audio CD from MP3s that can be played in a standard CD player. You may need to convert the MP3s to WAV first.
Audio CDs that play in a standard CD player has a file format .cda All other audio formats might be considered DATA for your software. It's important if you are making a disk full of WMA or MP3s or even WAV.