The auto-zoom function optimally adjusts the zoom level of the map at any time. This means that you do not need to zoom in yourself when you approach the task point or zoom out when one is checked and you navigate to the next task point.
Autozoom can be Activated / Deactivated via the Menu > Settings > Map & Layers > Enable auto-zoom
If you want to enable / disable autozoom during flight for any reason, you can do it via the Auto-zoom toggle button.
You can add it to the Map page just like any other Navbox. This is done by long pressing on a Navbox on the Map page > Add or via the Menu > Settings > Navboxes & Layouts > Buttons > Autozoom