Many times tasks come with a due date, but just putting in a due date isn’t enough. It’s easy to forget without reminders, so Priority Matrix has a built-in reminders tool. If you prefer to input your own reminders, go into the app and tap the task that needs a reminder. On the leftmost bubble, there’s a space for due dates. Click that and another row of bubbles appears. The first one is for “reminder” and tapping that lets you select the time for the reminder and the frequency of the reminders.