Collabora Office is a free and open source office suite for Android and iOS. It is powered by LibreOffice and developed (in part) by open-source consultancy firm Collabora.
But unlike previous ‘LibreOffice for Android’ style apps you may have seen this is a fully featured editing tool, not merely a document viewer.
It also features a bespoke UI crafted specifically for editing documents on mobile devices, via fingers. The UI borrows from the Collabora Online interface.
See Collabora Office Brings Power of LibreOffice to Android & iOS
Collabora Office is a free office app for Android and iOS built using the LibreOffice engine, making it the closet thing to LibreOffice for Android.