If you are not sharing your emails for a contact, you can turn on sharing by clicking change on the gray bar.
From the top of the contact timeline, you can see how many colleagues are sharing email with that client.
Clicking this will take you to a complete list of all colleagues who are sharing their email communication with the contact's email address.
Using the toggle, you can choose to share or un-share your email communication with that contact email address.
Each user in Karbon has a setting that will automatically share emails with all contacts in Karbon to increase visibility across email communication.
To turn this setting on go to your user profile by clicking your name in the main menu. You can then tick the box to auto-share email, and click Save.