The Matrix Activity Email will allow for users to forward emails into Matrix to create activities. The Matrix Activity Email address is different for each user.
You would find the address that is specifically for your profile and can download the Matrix Activity Contact vCard by clicking on your User Name in the upper right of the screen and then selecting Profile.
Once on the My Profile screen, click on the Integrations tab. At the top of the screen, the Matrix Activity Mail section will have the email address listed.
Clicking the Download vCard button, will initiate a download of the vCard file, which can then be saved in your default mail client, so you can utilize the email as a contact within your email client to easily forward messages to Matrix.