Hi, Firefox for Android supports basic bookmarking of sites but doesn't include the option to sort/organize bookmarks or group them into folders natively. If you need to organize your mobile bookmarks use Firefox Sync to connect Firefox for Android and Firefox Desktop. Using the Desktop Firefox bookmark management you will be able to arrange mobile bookmarks https://support.mozilla.org/en-US/kb/firefox-sync-take-your-bookmarks-and-tabs-with-you

Thanks