When you are setting up Freshdesk to use as a support portal for your company you will want to have something like email@example.com routed through to allow people to raise a ticket when you recieve a support query on that email address.
In Office 365 there are several options to do this. The following is what I believe to be the most straightforward.Office 365 setup
The first step is to make a group / distribution list which will recieve the emails.
Go to Office 365 and login then if you are not already on the admin pages click the blue box top left choose admin then on the netx page choose exchange from the left menu under the Admin dropdown.