Navigation: My Admin > Clients > Edit Client
Begin in My Admin and select a client. Once in a clients' workspace, you will find 'Contact Links' as the first page. There you will need to add multiple contacts who will bear different email addresses.
Upon adding those contacts, you should see them listed as below (a). You can also use the Default column to select one of those contacts to become the Default Contact of that client - this means the contact details of the default contact will appear on your client's list (b)
Once you've added the various contacts for a client, head to Practice Management. Once there, navigate to Workspace > Clients and search for the client or use the quick search button on the top right of the Practice Management module.
Once in that clients' workspace, head to Communication as shown below (c) and under the 'To' field, any default contact will be automatically selected (in our case, John) but the option to select any and all other contacts is done by selecting the checkbox.
Lastly, enter an Email subject, type the body and click send.