This is the new Firefox menu button. It consolidates and simplifies the old menu bar (File, Edit, etc.). Both the classic menu and new menu are available, however.

To switch from the Firefox button to the classic menu bar, click the Firefox button, hover over "Options", then click "Menu Bar" to toggle it on.

To switch from the classic menu bar to the Firefox button, click "View" in the menu bar, hover over "Toolbars", then click "Menu Bar" to toggle it off.

Thank you, Dave. Now I can "Copy" recipes within a link and "paste" them into my email. There might be another way with the orange tab. But I could not figure it out. I appreciate my ancient desktop, believe me! But, obviously, some things are beyond me! My 25 y.o. son is coming home for Thanksgiving. He is my support person..., but I was getting tired of copying recipes by hand. Thanks again, Noelle

The orange Firefox button's menu has little icons for copy and paste. You can also hover over the arrow to the right of those icons to see the menu with text labels.

You can also right-click on something you have selected and you'll get a menu that also has cut and copy in it. You can then right-click in a place where you can type to bring up that menu to paste.