To reshape a zone: tap ✏️ Reshape on its card below — white dots appear on the zone's corners. Drag any dot to move it (drag the faint mid-dots to add a corner), then tap ✓ Done to save.
To add a new zone: tap the ▰ polygon tool (top-left of the map), tap around an area, and double-tap to finish. Any villa whose GPS falls inside a zone auto-gets that zone's fare.