An article is a formal and informative content published in a print or electronic medium

An article is a formal and informative content published in a print or electronic medium. The primary focus of an article is to educate the reader. It can be of various types, like, feature news, academic analysis, and research results. It is written on a specific topic, usually nonfiction, in prose form and often in third or second person.
A blog is usually written in informal structure and is published online. It is like a website or a webpage which is frequently updated. A blog may impart fictional and/or non-fictional information to its readers. The most important feature here is that blogs enable readers to interact with the writer by leaving comments on a post. A Blog may be a personal online diary or it can be for advertising a company. It is often written in first person and in casual tone.
A press release is a formal written announcement to the media. It is written by public relations professionals to grab the interest of a journalist or publication. Basically, it is an official statement regarding company’s scheduled events, promotions, awards, new products and services, sales accomplishments, etc.