Within Teamwork Desk you can create a new inbox that your customers can contact for any issues they may be having.
When creating an inbox you will need an email address which will be the address your clients/customers will send their emails to.
Note: A user and an inbox cannot have the same email address.
To create the inbox click on the your profile icon to the top right of the navigation bar and select 'Settings;
In the settings area, go to the 'Inboxes' tab:
Select the 'Add Inbox' option near the top right:
You can now name the new inbox and enter the corresponding email address (e.g. email@example.com.)
You can also grant access to the inbox to existing users here, or add a new user.
When you click 'Next' you will then be brought to the forwarding setup screen:
Once this is set any email received to that email address will appear in the new Desk inbox you have created.
For more information see: Using your own SMTP server to send emails