A contact us a set user address that does not reside within your Microsoft Exchange 2013 organization. Addresses such as .onmicrosoft.com, gmail.com, etc.. Added contacts will be visible with your Global Address List and can be set to receive forwarded messages as well as being members of a Distribution List. 

This article illustrates how to create a contact to be used by each user under your account

1. Log into the Administrative Control Panel at https://my.securembox.com.

2. Under My Current Services, select Microsoft Exchange.

3. Under the expanded Microsoft Exchange menu, Click on Contacts.

4. The Microsoft Exchange Contact List will now populate with each contact you have created. To create a new contact click the Create New Contact link.

5. You will need to fill in each of the required fields to successfully create a contact. These fields are labeled with an asterisks (*). The optional information can be entered at any time.

6. Select Create Contact when you are finished.