my iphone xr keeps turning on and off and fallout to 1% even my batt percentage is higher

If you are seeng battery charge level at 1% that explains the erratic power and shutdowns. You need to get a good level of charge into your battery.

If your iPhone or iPod touch won't charge - Apple Support

Have you ever had your battery replaced? That might be the issue and with it being an XR it’s very possible that it is well below the 80% battery health level that indicates a replacement is needed