I need the address of friends in York England
Your question came to Finland, https://www.visitfinland.com/ . Unfortunately, we have no access to addresses in York, other than searching in the Internet. I found Ukphonebook.com, it's possible to search for a person there, https://www.ukphonebook.com/find_a_person . To make a search, you have to buy credits. You could try using Google, surprisingly often addresses can be found that way. Facebook is a place where you can easily find old friends also from abroad.
Royal mail seems not to have an address database, https://www.royalmail.com/ . You could also try contacting the City council, https://www.york.gov.uk/ . Contact information here, https://www.york.gov.uk/homepage/16/contact_us or a local library in York, for instance Acomb explore, https://www.exploreyork.org.uk/acomb-explore/ , contact information, firstname.lastname@example.org