Hi Walter If you are using a desktop copy of Firefox, this support article should help: https://support.mozilla.org/en-US/kb/find-and-install-add-ons-add-features-to-firefox#w_how-do-i-find-and-install-add-ons if you are using Firefox for iOS, it is worth noting that add-ons for the desktop and Android version of Firefox are unavailable for Firefox for iOS. Apple has created a proprietary iOS extension system which is incompatible with Firefox add-ons and extensions for Android, Mac, Windows and Linux. Also, iOS extensions written for other iOS apps won't work on Firefox for iOS (for example extensions written for Safari won't automatically work on Firefox for iOS).