The best way to go about attaching an email to a piece of work would be to either:
- go to the Work you want to attach the email to, click on "Email" and compose the email directly from there OR
- click on the Global Add menu (top right "+"), click on Email and then select the work you'd like to attach the email to.
This way the email sent will be attached automatically to the piece of work you want.
Note: the email will be automatically attached to the contact you are sending the email to as long as it's been added as a practice contact.