Then After ringtone was successfully imported to your iPhone using the 3uTools, you need to click on the “Settings”→”Ringtone” to set your personal ringtone.
Step1: please open the “Settings” of your iPhone, then click “Sounds”.
Step 2: Click on the “Ringtone”, then if you want to change the “Message tone”, then click “Message tone”. Message tone will be less than twenty-nine seconds can be supported.
Step 3: then after Choose your favorite one from the imported ringtones, then set it as your call ringtone.
[embedyt] https://www.youtube.com/watch?v=3Ht8i8v8Oas[/embedyt]