Doesn't matter. They can be added to your Music app regardless. They just need to be in the right file format to be added to iTunes. For example, .flac files are incompatible.
If it goes onto iTunes on the PC, it can go onto the iPhone. You might want to consider taking the option to transfer them at 128 AAC, as they'll take up less space with minimal degradation in quality.
Sent from my iPhone using iPF