If possible, navigate to the page that you want to link to, and copy the full URL from the address bar of your browser. The part of the URL that you need comes after the “dot com forward slash.” Otherwise, copy the URL Key from the CMS page that you want to use as the link destination.
Your store can be configured to either omit or append a suffix, such as .html, to the URL Key of product and category pages. Because this is a configurable setting, the suffix should never be hard-coded into the URL Key of a product or category. Omitting the suffix makes a URL easier to read, and according to some, may improve the quality of search engine indexing. Because the suffix no longer serves any particular purpose, its use is strictly a matter of personal preference. The important thing is to follow the suffix conventions that are in place for your store. You can find the configuration setting in the Catalog section of System Configuration, under Search Engine Optimizations.
Full URL to Category Page
Full URL to Product Page
Full URL to Content Page