How do I get my iPhone 13 to ring

Are you looking directly at the phone when the volume goes down? That would be the Attention Awareness feature. The phone recognizes that you are looking at it after the first ring and reduces the volume. It is to keep from annoying others. You can turn that feature off if you wish, go to Settings>Face ID & Passcode, enter your passcode, then go to Attention Awareness Features and turn that off.

jaqueline87 wrote:

How do I get my iPhone 13 to ring

Use the side control and flip the switch up for ringer.

My new I phone 13 pro will only ring one time on incoming calls

I have good volume for one ring