If you receive a customer support request email directly into your Outlook (or other email provider) inbox, and would like to have this logged in your Zendesk help desk as a ticket where the customer is logged as the requester, this may help:
If you are an agent, and agent email forwarding is enabled on your Zendesk
You merely have to forward the email into your Zendesk (e.g. by forwarding it to email@example.com). Zendesk will create the ticket without the FW: text in the subject line, and only the text below the most recent forwarding header will be added to the ticket.
If you are an end-user, or agent email forwarding is not enabled on your Zendesk
Type your ZD support email address (e.g. firstname.lastname@example.org) into the To: field
Type the customer email address into the "reply-to" email address field
Delete Fw: from the subject line (optional - but will make the ticket subject neater)
Delete the headers in the email body (optional)
The request will now be logged with the customer as the requester, and the usual notification email will be sent out to your customer by the applicable triggers.
Note that this method can also be used if you are an agent, and have forwarding enabled, but want to forward the ticket into your Zendesk with the requester set to someone other than the person who sent you the email. E.g. Sam sent an email to Peter, and Peter forwards the email to you. If Sam should be the ticket requester, you would use this methods instead of a normal 'forward'.
Where to find "Reply-To":
When using Thunderbird, press Enter after typing the zendesk support email address, then click on the To: button on the left in the second email address row - and select "Reply-To:".
When forwarding a message with Outlook 2007/2010, click "Options" tab and select "Direct Replies To", in the Properties field, change "Have replies sent to" to the customer email address. (Optionally Add "Direct Replies To" to the "Quick Access Toolbar" when composing a message. Saves on mouse clicks.)