Find the email builder under "Marketing>Emails".

Fill in who you'd like to send this email to, the template and the subject. 

After you're done making your final customizations, click in the txt block you'd like to attach your event notes in. The tool bar will open up where you can select "Merge Tags". 

Scroll down and select "Event Notes".

 You could create an automation to have event notes be attached and sent out upon completion of an event. Once you're done, preview and send!