In 1962, inventor and entrepreneur Alfred Levy found a loose wire touching a metal girder at his factory. It amplified the broadcast signal from the radio station next door and transmitted the audio through the loose wire to calls on hold. Four years later he patented his work, and music on hold was born.
While we are technically unable to put hold music directly onto a cell phone, there IS a way to have this feature and many other functions of an expensive phone system, using a cloud-based phone setup and a simple application on your smartphone. Whether you work on your cell phone exclusively, or you need an office phone (or phones) in addition

Someone is late for the conference call, so the music starts. "Well, I've been sitting here all day," the song begins, sort of croony, with a vaguely country affect — the kind of opening that leads you to expect there is, somewhere, an ex-lover who probably isn't coming back. A certain variety of pining. But then, a few bars in, a turn: "Yes I'm waiting on this conference call, all alone. And I'm on hold, yes I'm on hold... I hope it's not all day, ey!"
The information to include on your on-hold message varies depending what services you provide. A good starting point is to record the information you think a customer would need to know about your business, such as: Hours of Operation Location Services Provided Products in Stock Current promotions and offers