For something as simple as a contact form, this is one of the most complicated things to get set up and operating.
First, the contact module must be enabled. Go to
Administer >> Site building >> Modules and locate it in the list of core modules. Click the check box and go to the bottom to save the change.
Administer >> Site building >> Contact form. Here you can set up the "Categories" - or recipient name/office. [Don't confuse this with taxonomy categories.]
For example, email for the Sales Department might be given a category of "Sales." The email address that the form is sent to may be
email@example.com. If you want a reply automatically sent to the person sending the contact email, you can specify that here. Don't worry if you don't know them all right away, you can come back and change this at any time. Click the "Submit button."
Now click on the "Settings" tab. Here you can limit how many contact emails an individual may send in an hour -- this helps limit spamming. You may also turn on personal contact forms here; this allows users to contact each other. Click on the "Save configuration" button.
To me this step seems totally unnecessary, but I suppose that some people want it.
Administer >> User management >> Access control, locate the "Contact module" entry and enable it for the roles you want to be able to use Contact. Save your changes. The menu link (next step) will not be visible to any one not having access.
Administer >> Site building >> Menus. Under "Navigation," enable "Contact" as described in the instructions. Save your changes.
To add a link to a content page use
<a href="/contact">Contact Us</a>. Unfortunately, this does not give you the capability to specify which contact to send it to. Fortunately, there is help! Check out the Contact Forms module.