Well this depends, really. If you want to post an announcement such as an obituary, wedding, engagement etc. then contact your local paper and tell them what you are wanting to post and they will tell you the procedure for doing so. If you want to write an opinion letter then look in the opinion section and it will usually give you an address to submit your letters to and they will post it, if they feel it is worthy of being printed. But if you are just wanting to write an article you have to be on staff or a journalist for the newspaper company.