Oh! That means the charger given by companies/brand is also known as Quick Charger by Qualcomm and chargers available in market are called Power delivery charger or Universal charger.
You are slightly correct, pd carger is general charger this technology can be used to make any type of charger of any wattage for any electronic equipment, but qc is not, its like specific to device, precisely processor, like 7.5watt, 18watt, 27, etc, but some smartphone company implement thier own technology in charging, like oppo, realme, vivo, (vooc, dart, and warp) they are different for qc
