https://www.bleepingcomputer.com/news/microsoft/microsoft-to-do-for-android-and-ios-updated-with-new-features/

Microsoft To-Do is a free productivity app that allows you to manage your to-do list and synch it between the web, iOS, Android, and Windows devices. The Microsoft To-Do app was recently updated on Windows 10 with the star feature and today a new update is rolling out to Android and iOS versions with similar changes.

The Microsoft To-Do app on Android and iOS is getting the "Importance" feature that allows you to star tasks that you deem important. You can then sort your list of to-dos based on importance so that you make sure to get to the tasks that really need to get done.