It is not possible to edit the whole page at once, only one section at a time.
Samsung Galaxy S4, 5, 2GB RAM, Android 5.0.1
Reported by B.mertlik on cswiki (item 4). He said he doesn't speak English so asked others to report his issues with Wikipedia Mobile.
This will be a new option in the overflow menu when viewing an article:
- The menu item will have a caption of "Edit article", with the same "pencil" icon that we see for editing sections.