Why doesn't Apple 7 support ringtone customization?

This may be a setup problem; You can refer to the following methods:

1. First, select the setting indicated by the red arrow, as shown in the following figure:

2. Then click the notification and status bar in the red box to enter, as shown in the figure below:

3. Click the notification management in the red box, as shown in the figure below:

4. Click on the information in the red box, as shown in the figure below:

5. Finally, turn on the notification bell and vibration in the red box, as shown in the following figure: