This is an example page. It's different from posts because it stays in the same place and (on most themes) appears in the site navigation. Most start with an imprint, privacy policy or an “About Us” page to introduce themselves to potential visitors to the website. For example, it could say:
Hello! By day I work as a bike courier, by night I'm an aspiring actor and this is my website. I live in Berlin, have a big dog named Jack, like piña coladas, but less of being left out in the rain (without an umbrella).
...or something like this:
XYZ Company was founded in 1971 and has been providing the public with high quality products ever since. Located in a small city, the company employs over 2,000 people and supports city residents in many ways.
As a new WordPress user, you should your dashboard to delete this page and create new pages and posts for your site. Have fun!