You can only assign a task that appears in a shared list. There are two ways to do this:
- Tap on the task to open the detailed view. Then tap on the three dots on the right upper corner, then on the Move icon and choose a shared List. A box with a person’s name (usually you) will appear under the ‘Reminder’. Tap that option and assign the task to anyone included in that List.
- Create a List. Share the List with the person you want to assign the task to. Create the tasks inside the List. Make sure you attribute a date to that task, otherwise it will stay in the List but it won’t appear on the Today screen.