You can easily switch between your work and personal Microsoft accounts with multiple account support in the To-Do Android app. To add an account, tap your username and then Add account. Then just follow the prompts to add another account.
Once added, you’ll be able to see all of your accounts by tapping your username. To switch to a different account, you can simply tap to select it.
Please know that multiple account support is currently only available on Android, though we do plan to bring it to our other apps with future updates.