Adding an Email to Existing Calendar Event

Greetings alon36,

You can learn how to add attachments to a Calendar event on Mac here:

Add notes, a URL, or files to events in Calendar on Mac - Apple Support

"Add notes, a URL, or files to events in Calendar on Mac

You can add notes to events you create—a list of agenda items, for example. If you add a phone number to the notes, people can call it using their iPhone or Mac (if it’s set up to make phone calls). You can also add a URL to the event, and you can attach files, such as a form for an appointment or a document to discuss at a meeting.

1. In the Calendar app  on your Mac, double-click or force click an event.
2. Click Add Notes, URL, or Attachments.
3. Do any of the following:

• Add notes: Click Add Notes, then enter your note.
• Add a URL: Click URL, then enter a web address or other URL.
• Attach a file to an event: Click Attachments, then select a file to attach. You can also drag a file to the event info window.
• Preview an attached file: Select the file, then press the Space bar.
• Remove an attached file: Select the file, then press the Delete key."

Take care.

You can add an email address to the Notes field in an existing event - or a new event as you create it.

The email address in the Notes field is a hyperlink; when you open the event and click on the email address it will start an email to that address.

If you want to add an email itself to a calendar event, first print it to your Mac's desktop as a pdf, then you can drag it to the Attachments field or click on the Attachments field label to select the file wherever you have saved it.

Is there a way to attach the email itself so it will open in the mail app?

Not as far as I'm aware, no, which is why I outlined how to create the email as a pdf to attach that to an event.