Mac Mail


I work in Mac OS10.2.4 and need to send formatted announcements pasted into the body of email AND have the formatting and fonts preserved. I have AOL, which does not do it. I have been advised to try Mac Mail. I did register, and I took a "picture" of the Word document (command+shift+4) and pasted it into the email, and sent it out.I got an error message part of which reads:
>Send third party e-mail through port 587. This port requires you to authenticate and may require a change to your email client settings. Note, the server you are connecting to must support this configuration. If you are trying to get your AOL e-mail visit Keyword Open Mail Access, all others contact your server administrator for further support on this configuration.

Can any one tell me what this means and do you have a suggestion as to how I can make sure the formatting is preserved?