This information does not appear in your browser window. It is intended for search engines. The first META tag is a description of the page. This opens a new browser window to show you the coding of the page. You can close it when you have finished reading.
Many designers use comments to mark special sections of their pages - as in the following example.
They make editing easier at a later date. There are many other elements you might find in a typical HTML page - but these are the most basic. Remember that unless you open and close all your tags correctly, the page may not show up in your browser. See the page of common problems for examples.