Just like you would normally send HTML. Example below:
<%
myHTML="<html><head><style type=""text/css"">TD{font-family:tahoma;font-size:10px;}A:Hover{color:red;}</style></head>"
myHTML=myHTML & "<body bgcolor=""yellow""><table border=""0"" width=""450""><tr><td>This is a test email. "
myHTML=myHTML & " Were it a real email then the end of the world would be near."
myHTML=myHTML & "<br>You can view the end of the world "
myHTML=myHTML & "<a href='
target=""_blank"">HERE</a>"
myHTML=myHTML & "</td></tr></table></body></html>"
' the next line is not HTML - it will render as text after the HTML portion
myHTML=myHTML & vbcrlf & vbcrlf & "This is some text that is not part of the HTML"
myTo="you@somewhere.com"
myFrom="me@elsewhere.com"
myCC="them@overthere.com"
mySubject="EMAIL TEST"
myBody=myHTML
SET myMail = server.CreateObject("CDONTS.NewMail"

myMail.To = myTo
myMail.From = myFrom
myMail.CC = myCC
myMail.Subject = mySubJect
myMail.BodyFormat = 0
myMail.MailFormat = 0
myMail.Body = myBody
myMail.Send
Set myMail = Nothing
%>