How to set personal ringtone for vivo mobile phone?

Take vivo X20 mobile phone as an example.

operation sequence/order

1. To start, first find the application "Contacts" on the mobile phone desktop and click to enter a new interface.

2. Then enter the contact interface, find the contact who needs to set the ringtone, and click Open.

3. After entering the new operation interface, find the "default ringtone" option and click Open.

4. In the new interface, select the "ringtone" option.

5. In the new interface, just set the bell.