Powerpoint - new presentation change layout to portrait on iPad Pro

Looking to create a simple 1-page presentation in portrait layout

New>Options (Blank, Madison, Atlas, etc) ...no option for portrait

Design>Slide Size: only options are Standard and Widescreen ...no option for portrait

Home>Layout: no option for portrait

No icon for portrait / landscape

Google this question and seems many users have this same issue being unable to simply change the landscape layout to portrait. Please help.