menu bar
Why do all of the answers to questions regarding how to find or reveal the menu bar (in order to change settings) all require you to CLICK THE (NON-EXISTENT) MENU BAR?!?
Alla svar (1)
It sounds like you have found directions for desktop Firefox. Firefox for Android has a different interface so the help articles for desktop Firefox will not be helpful.
If you let us know what you are attempting to do then we can tell you if that is possible in Firefox for Android.
If you want to try searching the support site yourself the following link will only search the Firefox for Android help. https://support.mozilla.org/en-US/products/mobile