If you need a copy of a birth, death, marriage or civil partnership certificate that's been registered in England or Wales, you can order a copy from the General Register Office by HM Passport Office.
If you need a copy of a Decree Absolute, Final Order or dissolution of a civil partnership, you can contact the court in which the divorce, dissolution or annulment was granted.
The GOV.UK website has a search facility which can be used to find the contact details of the court.