How can make the online form submit directly to my yahoo email address? On the form editor, the drop-down box is only giving me the email address associated with my web site.
For security reasons, the online form mail must send email to the email address associated with your web site. You cannot change it to other domains within Mav SiteBuilder. However, you can configure your hosting account to forward email accepting from the form to other domains. You don't even have to create the real inbox for this address.
cPanel server:
You can forward email at cPanel >> Email Management Tools >> E-mail Forwarders.