How to check iPhone photo orientation before taking a picture – 9to5Mac:

How to check iPhone photo orientation before taking a picture

Open the Camera app
As you line up your shot, look for the magnification indicator (1x) next to the shutter button
Make sure it’s oriented in the same way you’re holding your phone
If it’s not, try rotating your phone back to another orientation and back to the one you want

Good tip -I have been caught out by this before.