In some cases you are your web site designer will  have pre-configured various page templates to standardize the look and structure of content managed pages on your site.

This selection allows you to assign a template to be used with this page.

Warning Changing the template for a page that already has content may have undesirable effects if the new template has a fundamentally different structure then the old template.

It is always safe to return back to a free-format page however.

Templates are very powerful and can dramatically simplify things if you have a series of pages that will all have a similar look and feel but different content. Templates are created and managed in the content manager however in most cases an advanced user with some knowledge of CSS and/or XHTML and perhaps even the back-end site coding should assist in setting them up.