As we have "residential areas", can we have "trade areas" and "office areas"?!
I think different places have different names for them. Where I live, I would say that we have residential areas, commercial areas (where the shops are) and industrial areas (factories, warehouses). "Office area" doesn't really work because there is no single definition of "office". It can be a room inside another building, it could be a whole block of offices, it could be just one floor of a building which houses other industries.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.