uses SHELLAPI;

procedure AutoSendMail;
var
  EMailDestinationString, SubjectString, Line1String,
    Line2String, mailstring: string;
begin
  EMailDestinationString := 'gbamber@bamber.com';
  SubjectString := 'Message Subject';
  Line1String := 'This is the first line';
  Line2String := 'This is the second line';
  // Можно использовать несколько адресов, разделяя их точкой с запятой
  mailstring := 'mailto:' + EMailDestinationString +
    '?subject=' + SubjectString +
    '&body=' + Line1String +
    '%0d' + Line2String;

  if (ShellExecute(0, 'open', PChar(mailstring), '', '',
    SW_SHOWNORMAL) <= 32) then
    ShowMessage('Auto method failed.');
end;