Dear user, you might think it does not matter. Why is the help desk being so anal? Can't they just call for more information if there's anything they don't understand? Can't they just forward the e-mail on between themselves?
The truth is it does matter, and with just a teensy-tiny bit more information and crafting in the e-mails you send to the help desk the chances are your issues will be resolved much more swiftly.
Let me take this opportunity to tell you how your company's help desk system most likely works because if its machinations are transparent then this helps you understand why you are asked to contact the help desk in a specific way. This becomes more and more important as the company continues to grow, with more staff in general and more IT team members too.
First, chances are high your emails aren't being received in the first place by a human being. Most likely it is software in place which monitors the helpdesk mailbox. Whenever you write to it a ticket number is assigned to your request. An e-mail is sent back to you with this ticket # as well as a link to use to view the status and progress of your request.
By using this system, multiple IT staff can view the help-desk queue and see what has not yet been allocated, as well as their own work queue.
There are important ramifications here.
For one, IT Managers, systems administrators, even individual help desk support staff are not across everything which is sent to the help-desk, and similarly IT staff may not necessarily be familiar with any specific request. If you send a request to the help-desk but then directly ask someone else the same thing without indicating it has already been logged you are making additional work because the history of your request - or even that it is already a request in progress - may not be known.