Wow! I can't believe how many people have subscribed to my channel! Thank you so much and I'm so sorry I don't upload more videos! I have been super busy!
I'm so sorry for the late reply! I'm not sure I understand the question. The song I used for my edit is Hold On by Chord Overstreet. But you may have heard the background music in that part which was just the soundtrack for Magnum P.I.
So just found this video and this fandom, so a year later on a response here but if you mean the ringtone Juliet sets for Magnum when he calls her, it is "Bang the Drum All Day" by Todd Rundgren.