Why does my iPhone keep turning off and back on?

All that you can really do yourself at this point is try a Forced Restart to see if that will help:

Follow the instructions very carefully, as this is a bit tricky. You may need to repeat this several times.

Force restart iPhone - Apple Support

There are only 2 possible results when you perform a Forced Restart:

1) The phone returns to normal operation

or, if the phone continues to restart.......

2) There is a hardware problem with the phone that will need attention at the Apple Store (make an appointment) or take the phone to an authorized Apple Service shop.

You can find a list of authorized service shops in your area using the link just below:

Find Locations

Good luck

AngelinaRuiz wrote:

iPhone keeps shutting off and on

[Re-Titled by Moderator]

Sounds like an issue

Put your iPhone in diagnostics mode - identify potential hardware and software issues

How to put your iPhone in diagnostics mode - Apple Support

iPhone Repair and Service - Apple Support

iPhone Repair & Service - Apple Support

Check Device Coverage

Check Your Service and Support Coverage - Apple Support

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment

Make an appointment for a "hardware issue"

Genius Bar Reservation and Apple Support Options - Apple

Outside the USA

Contact Apple for support and service - Apple Support