This is a sample page. It differs from a blog post because it remains in a fixed position and (in most themes) is included in the site navigation menu. It is common practice to create an "About" page to introduce yourself to your site visitors. For example:
Hi there! I work as a bike messenger by day, but I'm an aspiring actor by night. This is my website. I live in Los Angeles, have a great dog named Jack, and I like piña coladas and getting caught in the rain.
Or something like this:
The XYZ Doohickey Company was founded in 1971, and has been providing quality doohickeys to the public ever since. Located in Gotham City, we employ over 2,000 people and do all kinds of awesome things for the Gotham community.
As a new WordPress user, you should go to your dashboard to delete this page and create new pages for your own content. Have fun!