What is Microsoft To-Do and how does it work?
Microsoft To-Do is a personal task management app that empowers users to keep track of and focus on the things they need to get done. With apps for Android, iPhone, Windows 10, and the Web, Microsoft To-Do is also on every device you are, syncing automatically and securely via the Outlook Tasks API, meaning your data lives in Exchange and automatically integrates with Outlook Tasks.
User-level licenses for Microsoft To-Do have rolled out to tenants in most Office 365 subscriptions, so customers can configure their access to Microsoft To-Do on an individual basis.
In addition to controlling access to the app, users with enabled licenses for Microsoft To-Do see the Microsoft To-Do tile in the Office 365 App Launcher (in the “All apps” section) and on the Office.com portal (in the “Explore all your apps” section).
Please note that visibility of the tile depends on users having enabled licenses for Microsoft To-Do and Exchange Online.
Customers previously had access to an organization-wide on/off toggle for Microsoft To-Do, which enabled or disabled login for all users in the organization regardless of licensing. Since Microsoft To-Do is no longer in Preview, this toggle has been retired and users who update to the latest version of To-Do (1.19 or newer) will not be affected by it and their access will be based on licensing only.
Use of Microsoft To-Do with a work or school account is subject to a few conditions. In addition to an enabled license for Microsoft To-Do, users will also need mailboxes in Exchange Online for tasks in Microsoft To-Do to sync and store. Since these are crucial functions of the app, users without cloud-based mailboxes through Exchange Online will not be able to use Microsoft To-Do .
Since Microsoft To-Do uses Exchange Online for data storage and synchronization, customers benefit from the reliability, security and compliance they've come to expect. Data is encrypted at rest on Exchange servers and in transit to and from the Microsoft To-Do app on your browser or device.
The Microsoft To-Do web app hosted on https://to-do.microsoft.com is developed according to industry compliance standards (as are the native apps for Microsoft To-Do) and the web app has also been through audits, such as the SOC 2 (Service Organization Controls) Type 1 audit.
If you're the administrator for an organization, you can get help at Contact Office 365 for business support - Admin Help.