You can create folders and move bookmarks into folders. You can also put bookmarks into folders at the time that you bookmark them.

Finitarry that answer only applies to Desktop Firefox.

Firefox for Android supports basic bookmarking of sites. 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

Sorry, I did not realize it was for Android. Since the info about Firefox is now collapsed, I sometimes forget to click that button.

You cannot set up folders for bookmarks in Firefox for Android? You cannot organize them there? That seems a bit primitive. Even with Safari on an iPod, I can organize my bookmarks into folders.

Firefox Sync is a fine solution when it is working. For some of us recently that apparently hasn't been the case. Unfortunately it appears FF for Android is built on a model where Sync is available. There don't seem to be any native functions in the Android version to manage bookmarks like adding folders, importing JSON files from the desktop, or any other reasonable backup options for situations where Sync is unavailable.