Hi venig1004,
Thanks for coming to Apple Support Communities for help today. It sounds like you can't find previously purchased ringtones.
Check out: Use tones and ringtones with your iPhone, iPad, or iPod touch.
"Redownload ringtones purchased with your Apple ID
- Go to Settings > Sounds & Haptics.
- Under Sounds and Vibration Patterns, tap any sound.
- Tap Download All Purchased Tones. You might not see this option if you already downloaded all the tones that you purchased or if you haven't purchased any tones."
Since it also sounds like you don't see previously purchased music. You may have used another Apple ID to purchase this music and the ringtones.
iTunes tracks would not be able to be set as a ringtone.
Have a fantastic day!