Keep in mind that many employers prefer not to receive PDF resumes as email attachments because they may contain viruses or other malware. (livecareer.com)
One problem, however, with sending documents as email attachments is that you can end up acquiring multiple versions of the same document. (lawyerist.com)
Use the resignation letter as an email attachment and just create a message of introduction regarding your resignation in the body of the email. (template.net)