If it is in England ot wales and you have found the death in the GRO Index it will give a place name next to the entry, all you need is that place name, the persons name at death, and which quarter and year, then send to the register office that covers that distrcit, google say, Liverpool Register Office, and the name addy and phone number comes up, the certified copy will cost �7 plus postage, if you live near the register office, just acll in with the details and they will do a copy for you in an hour or so