Brother MFC-3240C - Manual (Page 161)

USING YOUR MACHINE WITH A MACINTOSH ® 8 - 39
Scan to E-mail:
In the General tab
You can enter up to a 30 character name in the Name for Custom
field. This name will appear as the button name.
Select the type of scan from the Scan Action field.
In the Settings tab
You can select E-mail Application, File Type, Resolution, Scan
Type, Document Size, Brightness and Contrast settings.