On Android, if you want to add a search engine that isn't preinstalled, you have to manually add it, which can be tedious and search suggestions don't work when they are added. To fix this, a user could tap and hold on a compatible search engine and tap something like "Add search engine". The desktop version of Firefox already supports adding search engines without having to manually type the URL, as seen on this guide: https://support.mozilla.org/en-US/kb/add-or-remove-search-engine-firefox