iphone 12 text alert sounds

Hello edythem,

Welcome to Apple Support Communities! It sounds like you need help with notification sounds on your iPhone. We completely understand why you'd reach out, and are happy to help.

See these standards steps for no sound and maybe something will fix it:

1. Is the iPhone in vibrate or silent mode? How to put your iPhone on vibrate, ring, or silent mode - Apple Support
2. How about the volume buttons? Adjust the volume on iPhone - Apple Support
3. Is Focus on? Use Focus on your iPhone or iPad - Apple Support
4. Go to Settings > Sounds & Haptics. Check the Ringer and Alerts slider.  Try changing the sound pattern for the type of alert.
5. Go to Settings > Notifications. Is the app listed?
6. Do other sounds work? What about phone calls? 
7. Do you have an Apple watch? Many of the notifications will go to the watch instead of the phone.

Please have a look and let us know if this helps! 

Cheers!