how to personalise ios16 lock screen on iPad Pro?

iPadOS 16.1 does not [yet] support lock screen customisation. Likewise, the active Astronomy and Weather Wallpapers are currently exclusive to iOS16.x for iPhone.

You can't, as yet.

Currently, iPadOS 16 does NOT support any Lock screen customisations.

Lock screen customisation is an iPhone ONLY feature.

Sorry.