Newspapers have editorial boards that take positions on certain topics. One of the members of the editorial board will write a column expressing the newspaper's opinion. They endorse candidates and espouse on various topics. These are the newspapers "official" opinions.
Newspapers also have "op-eds (so called because they are often physically "opposite" of the newspaper's opinion pieces, being on the opposing page) which are written by local or syndicated columnists and guest writers, which express the opinion of the writer himself, but not necessarily that of the paper.