How do I reduce photo file size in iOS 17

I need to reduce the size of photo files for export. I’m using Photos on my iPad 10 running iOS 17.7.1

Having searched the community & tried the routines proposed but none I have so far found work on my iPad. Perhaps I’m missing something but the subsidiary menus others mention seem to not be available in 17.7.

Can anyone explain in straightforward terms how to achieve file size reduction please?

Your help & information is massively appreciated.