It's the first icon in my post above which appears on each post when viewing a thread.
Are you talking about on the message composition page? If so you are in the wrong place and you need to go back to the thread contents page.
The image changes to when you click it to include a post for quoting.
I'm selecting the text and hitting the button until it goes red each time and then hitting post reply but I can't get it to wrap quotes individually.
Not to worry. I don't really need to quote. Just wondered as I didn't know how to do it and everyone seems to do it. Thanks anyway.