I'm assuming the email you're sending is an HTML formatted email? HTML itself provides for creating email links that autofill the subject and body. You can try that. Whether it always works or not might be dependant on the recipients email client, I don't know. And they still have to click send.
Here is the html syntax: https://www.rapidtables.com/web/html/mailto.html
Code:
<a href="mailto:joebloggs@home.com?subject=Confirmation%20Reply&body=Dear%20Hot%20Stuff%2C%0D%0A%0D%0AThank%20you%20for%20your%20email%2C%20this%20is%20to%20confirm%20we%20have%20received%20all%20items%20therefore%20please%20sign%20for%20these%20on%20our%20behalf">joebloggs@home.com</a>
Also, outlook can send messages and ask for read receipts. Again, that depends on everyone using outlook and the recipients not being difficult contrarians that turn off the read receipt features like I do. https://www.technipages.com/outlook-enable-read-receipt
Junes idea is a good one if you access to a server.