Azizi, when describing urban localities in the US you used several terms to refer to them, including Subsections", "Neighbourhood" & "Borough". I suspect only the latter two are 'formal' and guess most British and Oz 'catters would be familiar with the terms because of the tsunami of American cultural material in our cinemas (called film theatres by older Australians) and on the telly.

My impression is that those in the UK (rarely describable as "Great Britain" these days) would probably use those terms only rarely and more commonly say "suburb" if informally describing an urban locality with its own name, and might refer to County or Shire if describing a more rural locality with its own name. If giving the formal name of a Municipality or Local Govt Area they probably have even more specific terminology.

NSW & Sydney started with a very English approach to such nomenclature so there "are" Counties but only a couple get referred to as such in colloquial use, but cadastral (municipal) maps will refer to both Parish and County as descriptors; I've only heard "Parish" used (in naming a locality) to refer to church boundaries and then only to Anglican or Catholic churches. And even the term Anglican instead of Episcopalian because of how the latter term is used in the SE US. "Suburb" is the usual term for an urban area with its own name in most of Oz.

Outside the original settlement area of greater Sydney, rural Local Govt Areas (Municipalities) with one or only a couple of small townships would be called "Shires" and only be regarded as a "City" if the township had more than 10,000 people (at least it used to be like that in Victoria) and, although they might be large enough to have differently named subsections, such subsections often had no formal nomenclature.

Confused? Join the club.

UK, GB, England etc?
It depends on how polite you want to be. It's never a good idea to refer to anywhere outside England (but part of the British Isles) as "England"; most denizens will be most snaky at such treatment. They may be more accepting of being called "British", depending on their politics but context is everything. Aussies have a reputation of enjoying stirring the Poms but some of us have learned how to be nice. Some of the time, anyway. UK is the usual last bit you'd put on an envelope you're sending by snail mail, much the way USA is the last bit for sending to that part of America north of the Rio Grande but south of the 39th parallel.

And the locality descriptor you call a Zip Code, the Poms and us call a Post Code.

Hope this is helpful.

Cheers, Rowan