In desktop Firefox for Windows, macOS, and Linux it has been Settings for a while now in the three bar hamburger menu.

https://support.mozilla.org/en-US/kb/firefox-options-preferences-and-settings

By "Orange Firefox tab" you probably mean "Firefox View". Right-click the 3 bar menu or a tool bar and select "Customise Toolbar". You will see what you want there and can drag it to the tool bar.

https://support.mozilla.org/en-US/kb/how-set-tab-pickup-firefox-view

If you were referring to an old Firefox version like with Options/Preferences that is now Settings, then with the orange Firefox button you might refer to the "3-bar" Firefox menu button that was orange a long time ago.

• https://support.mozilla.org/en-US/kb/restore-menu-bar-firefox