Uses Frontier Developments official iOS API (aka Community API) to connect and download commodity market prices, shipyard ship sales and outfitting modules information. It then sends this data automatically to EDDN with single click of a button, or a keyboard hotkey or even automatically if so configured in settings.
It also updated EDSM for your flight logs etc.
Early days of Elite we had to use manual pencil and paper, then we got the OCR solutions which were somewhat cumbersome and poor, but now finally we have EDMC which uses the API, makes no mistakes and is automatic (you only have to click a button).
EDMC Homepage in github