Brother MFC-8820DN - Manual (Page 254)

USING THE WINDOWS ® -BASED BROTHER SMARTUI CONTROL CENTER 15 - 17
Scan to E-mail
The Scan to E-mail is automatically configured to your default E-mail
application. To change the default E-mail application or attachment
file type, right-click on the E-mail button and select “Configuration”.
The Scan Action tab is set to E-mail and should not be changed.
To change the E-mail application click on the Configuration tab. From
the Application pull down list, select your preferred E-mail
application.