This is an example of a page. Pages are different to blog posts in that not only are they always in one place, but they also appear in the site menu (in most themes). Most users start with a page of information about themselves, which will introduce them to visitors to the site. Such a page might include text like this, for example:
Hi, by day I am a bicycle courier, by night I try my hand at acting, and this is my website. I live in Krakow, I have a wonderful dog whose name is Reks and I like piña coladas (and walks when it rains).
...or something like that:
XYZ Doohickey was founded in 1971 and has been providing the public with quality goodies ever since. Located in Gotham City, XYZ employs over 2,000 people and does amazing things for the Gotham community.
As a new WordPress user, you should go to its cockpit to delete this page and create a new one with your own content. Have fun!