GeoStamp is a free and easy-to-use app to watermark your photos. The in-photo stored EXIF location data is reverse geocoded using the OpenStreetMap API, so the name of the place can be placed as a tag on your photo. The app also works as a Photo Extension or in standalone mode. In extension mode it allows you to edit your photos one by one while in app mode it offers a bulk-tagging feature. You can choose from multiple styles and fonts for the tag. And last but not least the app is free and ad-free, so just download and enjoy! :)