
A registered office is the legal jurisdiction that the company falls into. For a UK company it would simply be 'England and Wales' or "Scotland". The statement as to the registered office in the memorandum fixes the company's nationality and domicile.
This is the address that all the statutory documents pertaining to the company e.g. register of members, memorandum etc.. are kept. Further documents relating to legal process (writs, summonses etc) can be served on the company by leaving it at or sending it by post to the registered office of the company.