Templates often look like text boxes with a different background colour than that of normal text. They have their own namespace called Template:. You enter them into a wiki page by using the appropriate template tag: {{UnderConstruction}} (try adding this template when you feel the page you are writing still needs more work).
This technique is commonly known as transclusion.
References: Wikipedia:Help:Template | Wikipedia:Template_messages
- Help trascludes from [{{SERVER}}{{localurl:{{NAMESPACE}}:{{PAGENAME}}]
- Help|action=edittrascludes from [{{SERVER}}{{localurl:{{NAMESPACE}}:{{PAGENAME}}|action=edit]