The best option I can think of right now is to use the Email Button component. That allows you to specify a recipient, subject, body of message etc. You can set the action in a button to send an email, but for some reason you can’t set the subject, body, etc.
To get a copy of your sheet as a PDF, look at the following thread which shows how to create a link that will do that for you. You can include the link in the email and the link will always create an up-to-date PDF version of the sheet.
This is another thread that talks about using scripting.
