iPhone PC Suite is a powerful assistant for iPhone. With iPhone PC Suite, you can change your ringtones easily and quickly.

Step 1: Connect your iPhone to your computer and run iPhone Pc Suite. Then click the Media button. Click Ringtones to enter the Ringtones interface.

Step 2: Select the ringtone type you want to change. iPhone PC Suite allows you to change system sound or call ringtone by clicking the System Sound button or Call Ringtone button, which are available on the left side of the Ringtones interface.
 

Step 3: If you want to change your call ringtone, click the Add button, then a dialog box will pop up. Select an audio file which is convertible by LP, then LP will automatically convert the file and upload it.

Step 4: After the upload completes, the ringtone will be shown on the User list. Select it and click the Set as Ringtone button to change your current ringtone.

Step 5: If you want to change iPhone system sound, just click System Sound, then you'll see a catalogue on the right side. Choose the one you want to change system sound for and then click the Replace button.

Step 6: Then a dialog box like below will pop up. Choose an audio file to replace your system sound. Note: iPhone only supports CAF, AIF and AIFF formats.