When I try to install Creative Cloud on an iPad the error readout is that I must have iso 12.0 or later; when I try directly installing LR Mobile it baulks because it reuqires ios 12.3 or later. I have ios 13.3 installed.
Are you trying to instal them from the App Store? When you search for Lightroom at the App Store, you will find two versions, one for the iPhone and one for the iPad. Makes sure you install the iPad version.