I just received my Samsung S9 a couple of weeks ago and noticed that I couldn't change the ring tone and message notification to a custom one by default. However, I did find a simple solution that may help others.
- On a memory card (or root device folder), create a folder called "Media"
- Inside the Media folder, create a folder called "Ringtones"
- Create another folder called "Notifications"
- Anything you put in those folders will appear in the Sound Settings
I hope this helps anyone. I was constantly missing calls because I was used to a specific mp3 that I had on my previous phone.
