Open your phone, click on the WeChat icon to run it.

After running WeChat, click Me in the lower right corner of the main interface and find the settings in the pop-up interface.

Click to enter settings and find new message notifications in the pop-up interface.

Click to enter the new message notification option and find the incoming call ringtone in the pop-up interface.

Click to enter the ringtone option and find the replacement in the pop-up interface.

Click to enter the replacement. You can use the search function to search for ringtones, or you can choose the ringtone recommended by the system. After finding the ringtone, just click "Set as ringtone".