MP3 is one of the most popular audio formats for ringtones. It offers high-quality sound and is compatible with most modern smartphones. You can easily find MP3 ringtones online, and they are versatile, allowing you to use songs or sound effects.
M4R is the standard ringtone format for iPhones. If you own an iPhone, it's best to use M4R ringtones for seamless compatibility. You can create M4R ringtones from your existing music using iTunes.
WAV files are known for their high-quality audio. They are compatible with many smartphones, but due to their larger file size, they may take up more storage space.
OGG is an open-source audio format that's popular among Android users. It provides good sound quality and is compatible with most Android devices.