To change your ringtone to a song, the process varies depending on whether you have an iPhone or an Android device.

For iPhone:

You can use the GarageBand app to create a custom ringtone from a song. The steps are:

• Download the song you want as your ringtone and save it to the Files app or have it downloaded in Apple Music.
• Open GarageBand, select Audio Recorder, and import the song into the workspace.
• Trim the song to a 30-second section.
• Export the trimmed song as a ringtone via the Share option.
• Once exported, set the ringtone in your iPhone's sound settings.

Alternatively, you can buy ringtones directly from the iTunes Store and set them as your ringtone.

For Android:

• Ensure the song file (MP3 or similar) is downloaded on your device.
• Go to Settings > Sound & Vibration > Ringtone.
• Tap the plus sign to add a new ringtone.
• Select the song file and save.
• The song will be available as your ringtone from the list.

These methods allow customization of your ringtone with a favorite song on both iPhone and Android devices.