Parents can only recieve this message if they have an active connectED account. If they don't have an account, you will need to create the account. See the solution article on how to create the connectED accounts for parents.
(Note if you don't see more tools check your permissions)
Click on Send Account info>Prent needs to be selected as the group and your search criteria is set before you click search
You may select all parents or the ones you wish to email by clicking on the box before the name. To select all, click on the box about the first parent.
Make sure the only option on this page selected is 'Include Note'
Type your message where it says, 'Type your notes here'. 
When you are ready to send the email click on the white envelope bottom right corner of your screen to send the email. (Keep in mind once the email is sent you cannot retrieve or unsend the message.)
If you wish to do a test before sending out to the parents. You can change a parent's email address to your own and select Individual instead of grade then follow the other steps. 
This is a sample of what the email message will look like, the highlighted box is the message I entered under notes
