I’m trying to update my iOS but it seems to be stuck on update requested? How can I move forward with an update?

Try turning off WiFi on the phone and then force restart the device. After the phone fully reboots, turn on WiFi again and see if that starts the download process.

This is how you force restart the iPhone Xr. Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then press and hold the Side button until you see the Apple logo. When the Apple logo appears on the screen, let go of the buttons and let the phone start up.

Restart the phone and try again.