On the setting page of Apple's mobile phone alarm clock, just select your own music to change it, which is divided into three steps. The operation steps are:

Tools/materials: iPhone12, IOS15.1, local setting 1.

1. Open the alarm clock editing page

to enter the Apple alarm clock and open the "alarm clock" editing page.

2. Enter the ringtone setting page

On the alarm clock editing page, enter the ringtone setting page.

3. Click to select a song

Click "Select a song" to select your own music or set the ringing tone.