Wystarczy tyle:
Dear Sir/Madam, (alkbo po prostu ...To whom it may concern)
I (imie i nazwisko) hereby give you official xxx(tygodni/miesiecy) weeks/months official written notice that I wish to resign from xxxxx(firma) as from xxx (data).
(Jak chcesz dopisac, zeby wszystkio bylo zakonczone to...Please ensure that you forward me the necessary paperwork (including any owed wages/holiday pay), so that the matter can be finalized.
Thank you,
Podpis i data.