Choose &lt;b&gt;enable&lt;/b&gt; to have an auto-reply message sent to the requester when a new ticket is created. 

Choose &lt;b&gt;disable&lt;/b&gt; and the auto-reply will not be sent.

The template for the auto-reply can be found at:

Settings -&gt; E-mail -&gt; Templates -&gt; Helpdesk