Delete a list
To delete a list, tap or click the three dots in the top right corner of your list to access the more menu. Then, select Delete list.
Restore a list
Since your lists are stored on Exchange Online and are also visible in Outlook Tasks, you can recover accidentally deleted lists in Outlook:
1. Sign in to Outlook on desktop with the same Microsoft account that you use with Microsoft To Do.
2. Navigate to your email folder list, then select Deleted Items.
3. Locate the deleted folder, right-click it, then select Move > Other Folder > Tasks.