An EHR/EMR is a core system. Most of the more recent ones are capable of accepting add-ons, or sub-routines, that add to the functionality of the EHR/EMR.
One such add-on are software programs that will scan the notes the doctor types, looking for key words or phrases. The software will then generate a list of CPT and/or DX codes, or both - depending on the sophistication of the software. The software can be set to automatically assign these codes to the patient for that date of service, or to present them to the doctor to let him decide which codes he wants to assign to the patient.
Most physicians avoid EHR generated medical codes. Is that true ?
I don't know how such a statistic would get compiled. Perhaps by survey, but survey's are notorious for their low response rates. So I would be wary of the word most. But I imagine most doctors would like to be certain that their patients are being coded correctly, and so would at least want the ability to pass judgement on whatever set of codes some software program generated for a given patient on any given date of service. That makes sense to me.