Generally speaking a contact us form works in two ways.
1) using the anchor tag with a href attribute containing mailto:
This will open up a fresh little email with the information you specify as mailto attributes, but does not send it.
2) you fill in a form which is submitted, but contrary to popular belief, this does
not send an email! This instead inserts the data into a database. The data can then be read by the people you are contacting, or indeed with ceertain DBMS a trigger event can fire which sends an email containing the stored details.
Hope this helps; feel free to ask questions as always
