The Window menu toggles every palette: Swatches, Text, Info, Pages, Separations, Bookmarks, Annotations, Signatures, Edit (the inspector for the selected element: colour, fill, thickness, opacity, dashes), Tags, Document Info, AI Console, Feedback. Reset Palettes… puts them all back where they started.
Press Tab to hide or show all palettes at once (not while you are typing). Palette positions and sizes are remembered between launches. When the Edit palette opens for something you just selected, it parks itself beside the selection instead of covering it — and if you drag it somewhere yourself, it stays where you put it.
Edit ▸ Keyboard Shortcuts… opens a browsable list of every shortcut in the app, and Help ▸ Pdf Editor Help opens an in-app help window built from the app's own menus and tools, so it is never out of date.