How to Move Your Mac Dock to the Side (or Make It Full-Length)
To move Apple's Dock to the side, open System Settings → Desktop & Dock and set Position on screen to Left or Right. Apple only offers Left, Bottom and Right, and its Dock never stretches from edge to edge. For a top-edge dock, a full-length dock, start or end alignment, or a dock sized to each display, use Moor: press Control-Option-E and use the Placement menu, or set every option in Settings → Docks.