Select the Email Archive tool from the Tool Menu of your site.

Choose the radio buttons for the settings you want to enable. You can customize the following settings:

1. Accept Messages From: You can choose to allow anyone to send mail to the Email Archive address, or to allow only site participants to send mail.
2. Set the reply-to address: You can set the reply-to address for messages sent through the archive so that users automatically reply to the original sender or to the Email Archive address.
3. Send messages to: You can choose to send email to site participants as well as archiving the messages, or you can choose to archive messages without emailing the site participants.

If you would like to customize the site email alias to make it easier to remember, you can modify the address here.