So, by sending those two links you assume I didn't read those first? Ah, okay ...
Back to the original question:
How do you respond to the email that someone sends you back? So you remain hidden? So you don't use the address the forwarded email came to? Because that would defeat the purpose, wouldn't it?
You've created the email, it's in your iCloud, you've used it, it's saved. Now, someone sends you a note. The hidden email is sent to a gmail account or some other account in your Apple Mail. How do you respond to that email without revealing the address that the hidden email was forwarded to?
According to this, I have to sign into my account - well, I have to start the account, put in my user name, put in my password, go to the emails, find the one that corresponds to the forwarded address - and hopefully the responding person is identified (I used this to get an answer regarding a product where I didn't want to be hounded by advertising), then copy the hidden email address, go to apple mail, open "new", paste the hidden email in the From and write them back. Right ? that's the Easy way?
If this answer is buried in the link word salad my apologies, but I don't see it clearly. I have read the missives twice now.