Collabora Office is a free office suite like Microsoft Office, but runs on your mobile device.
Collabora Office for Android and iOS is available for download from the Play Store and the App Store and also available for F-Droid. The latest snapshot for Android is also available for download as .apk. The required Android version is 5.0 or later. The required iOS Version is 12.2 or later and is compatible with iPhone, iPad, and iPod touch. Learn more about their mobile office suite on the product page or visit the credits to find out who has been involved.