Content pages are the workhorses of the site, with the information people want on them,

the standard content page, contains a content area where you can enter any content you want to appear on a page, and a related section that allows you to add additional links to the page.

Content 

The core content of the page, such as title and content. the Content Editor is the standard umbraco editor, we have added some extra formatting under the formats drop down that let you specify things like heading and alert boxes. 

Related

related links allows you to specify pages or other sites that might related to the content on this page.

Page Info

As will all pages content pages have a page info tab,

Page Summary lets you specify the text that is used on navigation pages (like gateway pages) when this page is displayed.

Service Alert: Allows you to add an alert to the page, service alerts always appear across the top of a page, and are designed for those times when you need to tell people something important about a service (like, you can't take payments just now because the system is broken)

Contact Details: Selecting a contact node for the contact details will cause a contact details element to be rendered on the page, this will include links to telephone and email addresses as well as an online form the user can fill into to contact you. 

By not including phone numbers directly on a page, you are giving yourself the ability to measure how many people actually click on the links and contact you - this can give you a good indication of how well a page is meeting the user's needs.