https://techcommunity.microsoft.com/discussions/microsoft365apps/onenote-for-ios-iphones-only-1602500-19043000-beta-build-for-test-flight-now-sho/530393
OneNote for IOS (Iphones only) 1602500.19043000 (beta build for Test flight) now show Sticky Notes...
as an icon at the bottom of the screen