You can find the window in two ways:

1. Choose Preferences from the Setup menu.
2. Click the Reports & Forms tab.
3. Click the Emails button

--OR--

1. Click Print/Email Statements in the Sales Command Center.
   
   or
   
   Click Print/Email Sales in the Sales Command Center.
   
   or
   
   Click Print/Email Purchases in the Purchases Command Center.
2. Click the To be Emailed tab.
3. Click the Email Defaults button