Posted 10/3/2019 12:53 PM (GMT -7)
Since life is always complicated... There are different widgets on the screen depending on which browser you use. If you use one of the Microsoft browsers (Internet Explorer, Edge) then Tud's explanation is sufficient. On the other hand, if you use Firefox you will see a "Post Quick Reply" text box under the "+New Topic" and "+Reply" buttons.
The "Include Signature" box only appears when you reply using the "+Reply" button. If you simply type a response into the "Post Quick Reply" area (as I am doing now) your signature seems to always appear if you have one defined.
So, if you don't want your signature to appear and if you are a Firefox user then you have to be sure to press "+Reply" to bring up the "Include Signature" check box.
Oh, and like the man said, it is usually better to allow your signature to show, at least in on-topic threads. The information in your signature helps other members remember who you are and which topics you know about from personal experience. It also helps avoid getting advice that doesn't apply to your situation.