Geotagging is where your photos are tagged with location data. If you clicked a picture in NYC, the photo's meta data (called EXIF) will have this location information embedded to it. It's useful when pictures are sorted according to location.
But sometimes you might like to keep those locations or visits personal. You might not like to add your location to the photo each time you click one. Your iPhone lets you disable geotagging so your photos do not have the location data.
How to turn Photo geotagging on or off on your iPhone/iPad
Step #1. Go to Settings app → Tap on Privacy.
Step #2. Select Location Services.
Step #3. Tap on Camera.
Step #4. Tap on never.
You can always change the setting for next use. Enabling/disabling the location services privacy settings does not affect the functioning of GPS of Apple Maps or Google Maps.
Disabling geo-tagging has a few side-effects. First off, since the EXIF data no longer contains information about location, you won't be able to create albums based on location/places for these photos. If you have the habit of filtering/tagging photos based on the location, you might not want to turn off geotagging.
Also note that this disabling only works within the stock camera app. Other apps that access camera (like Instagram, Twitter, Facebook, Camera+, Whatsapp) will still be able to tag location data to your photos. This is because these apps might have the permission to use your camera and your location data (and the apps can club both.)
If you want to be Snowden and keep privacy a top priority, you might want to disable location services completely (which will, of course, affect your Maps and GPS experience.)
And, photos that were taken before turning off this feature will still have the location data. You might have to use some EXIF-editor to get rid of the data.