Regular residential uses 6'8" doors. Commercial is usually 7'0" and premium office space uses doors in the 8' neighborhood.
I once got to install an entry door of Brazillian Mahogany with what looked like an automobile grade baked on finish. It did have a side light (window) too but the price tag was $7,500. The other carpenter was afraid to unpack it after he saw the price tag. Even though I missed work the day of delivery due to a Trump size hangover (HUGE), they waited for me. I'm kind of proud of that. I installed that entry mostly sober too.