I don't know if the landlord means that there is a ringtone option in itunes and the music has been synchronized, but there is still no ringtone in iphone. If so, the solution is as follows:

Apple has made strict regulations on the duration and format of iphone ringtones. If itunes is out of sync for more than the specified time, even if the landlord is synchronized, there is no ringtone in the iphone, so what the landlord needs to do before synchronization is to make the ringtone into the specified ringtone. First, the landlord adds the music to be set as ringtone to the database (click on the file in the upper left corner of itunes, after adding, find the added music file in the music, right-click the music, find the display introduction, select the option, fill in the "start time" and "stop time" (within 40 seconds),-"OK", right-click the song, and select "Create ACC version", then a music file with the same name will appear. Select "Display in windows Explorer", change the format of "m4a" to "m4r", and select "Yes" in the pop-up window. Ps: If you can't see "m4a", select "Display in windows Explorer", select "Folder Options" in the menu bar and select "View". Then connect the iphone and sync in Ringtone.

Well, that's the end of the answer. If the landlord has dissatisfaction and support, you can continue to ask questions. Finally, I wish the landlord a happy day.