The entire article is speculative, so there's room for error ["Was Hillary wired for Trump debate?"]. But there are some basic answers to the questions that are posed.
There is a lavalier microphone on both candidates that requires a transmission device to operate. Having these on a candidate is standard procedure for any competent audio-visual team in a live event setting. In truth the lavalier is used as the main pickup source because it can pick up the audio even if the speaker turns his or her head. In these situations the hard-wired lectern microphone is used as a backup to the more flexible lavalier.
The transmitter is normally placed on the belt or in a jacket pocket. For Secretary Clinton it was clearly placed on her belt (or attached with a separate microphone belt) and placed at the small of her back for comfort and to remain minimally visible. For Mr. Trump it was probably placed in an inside pocket or simply isn't visible on his belt because of the looser fit of his jacket.
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I am a professional in the live events industry and can confirm this assessment with no speculation, rather with an educated understanding of the situation.
There's nothing in her ear. Your own photos prove that.