You can enter your e-mail address in the "Company E-mail" fields. This E-mail will be used as a back E-mail address for your customers or vendors. If you already use the mail programs such as Outlook Express or MS Exchange, your messages will be sent through them.
Otherwise, you need to enter the "Outgoing Mail Server (SMTP)" address that is used to send all the out-going e-mails. You can find this address at your Internet Service Provider. For example, SMTP address is "smtp.provider.com". If your provider use authentication SMTP connection you should set check box "Use authentication" and enter your user name and password.