There are many ways to change the notification sound on your iPhone. There are three main types of ringtones: Active Grade, Meeting Grade, and Custom. The latter is the most common choice, as it allows you to set the tone for the specific person you're calling. Listed below are some of the most popular options. These can all be downloaded and used for free. Some tones are even professionally produced and have a wide variety of formats zigtone.com

AMR was the first format for ringtones. It is an audio compression format used by Nokia before MP3 was the standard. eMelody was a monophonic format developed by Nokia and later replaced by iMelody. Users can also share ringtones using text messages. A Palm database is also used to load ringtones on many mobile phones. The PMD format was developed by the Digitalphone Group and Faith. It has many features like MIDI and static graphics.