for each task, when assign a date reminder. I want to know if i can search or oveview all the tasks easily
You can search at the note level. In the search bar at the top, there is a calendar icon on the right. There you can choose a date or range of dates, and any notes with that date should be shown.
But this is not at the task level, it is at the note level. We don’t yet have a way to filter for individual tasks (check items). We have plans to support that in future.