Locked ipad

1. Make sure that Rotation Lock is off:

• • On an iPad with iOS 12 or later, or iPadOS, swipe down from the top-right corner of your screen to open Control Center. Then tap the Rotation Lock button  to make sure it's off.
  • On an iPad with iOS 11 or earlier, swipe up from the bottom edge of your screen to open Control Center. Then tap the Rotation Lock button  to make sure it's off.

1. Turn your iPad sideways. 

If the screen still doesn't rotate, try a different app like Safari or Messages, which are known to work in landscape mode. If the screen still doesn't rotate, check to see if your iPad has a side switch.

To enable or disable Screen Rotation, you need to access the Control Centre. Swipe downwards from the top-right corner of the screen - then tap the Screen Rotation lock icon:

If screen rotation proves to be problem with some Apps - and not others - you need to be aware that not all Apps are coded to operate in both Portrait and Landscape screen modes. Apps that have a fixed screen orientation will always appear in the orientation determined by the App Developer.

I hope this information and insight proves to be helpful.