Before creating the ringtone, you will need to prepare your audio source. You can use audio editing apps to cut the part you want to use as a ringtone. Make sure you select the most relevant and melodic part of the audio.
Most phone ringtones last 15 to 30 seconds. Make sure to set your ring duration accordingly. You can do this by cutting the audio file to the desired length.
Phone ringtones are usually in MP3 format. Make sure your audio file is converted to MP3 or a format compatible with your phone. There are many free online applications to perform this conversion.