Why is the MS To-Do App adding things to my reminders, and how do I stop it? I have a corporate Office 365 account for work and have the Microsoft To-Do app installed to manage work related things. 

When I add a task, it seems to be added to my iOS reminders:



I haven’t given (or has it asked) permissions to access my reminders:

I use the Reminders app for personal stuff so don’t want this to happen. There is nothing in the To-Do app settings to disable this “feature”.
Your Microsoft account may be syncing with your iOS device. To disable this, go to Settings > Passwords &amp; Accounts > (might be called Exchange or Outlook) > Disable Reminders. If you want to disable all syncing with the account, you can also remove the account entirely from your device.