Give an item a Location — pantry, fridge, freezer, garage — on its edit screen: tap Location and pick one, or choose New Location… to make one right there. The location shows under the item’s name on its screen.
To add, rename or delete locations, go to Settings → Pantry Locations. Tap + to add one, tap a location to rename it, or swipe it to the left to delete it. Deleting a location takes it off the items stored there; the items themselves stay.
To see what’s in one place, tap the filter button on the Kitchen tab and choose Locations.