When a PLAY verb is present in a dialplan, your defined audio file (in .wav format) will be played.

  "type": "PLAY",
  "repeat": 3,
bargeInIf the value is true then the first DTMF tone during the verb interrupts the current execution. All the collected tones of the call, including the tone that interrupted execution, are sent to the eventUrl.
The default value is false.
repeatDefines the number of repetitions. Default value 0. Set to "-1" for infinite loop.
fileURL*The url of the prerecorded wav file.