Most tire shops and service centers go by the door sticker--and it's a bad idea because it doesn't take into account your actual load and whether you've switched from P-metric to LT (surprisingly, LT tires require more pressure than P-metric for a given load).
The Tire and Rim Association sets the standards you're looking for.
Look here for the inflation / load values for your particular size and type of tire:
https://tirepressure.com/tire-sizes
or
https://www1.prodemand.com/Content/Pdf/tg_passenger_load_inflation_tables.pdf