Do you mean when you're looking for a Multi-cache?
If so, in the iPhone App, go to 'Navigate to Geocache'
Then click on the flag icon in the top right corner of the screen, name it a particular waypoint or GZ, then enter the Latitude & Longitude and click 'Done' in the top right of the screen.
This will take you back to the 'Navigate to Geocache' map but now you should see a flag on the map for the new waypoint you just entered. Click on the flag and you will now be navigating to the new waypoint. If you click on the cross hairs icon on the left middle of the screen you can change the focus to 'Navigation Path' to make it easier to get to the new waypoint.
You can also use the 'Notepad' in the Geocaching App to save your workings and notes for the individual cache to go paperless & to refer back to anytime.
I hope this helps?!
AzzAndJadey