When you create new post, you can add a due date for the entire post or add individual ones for each assignee. Both you and the assignees will receive notifications for upcoming and past due posts, based on these due dates.
After you add assignees to your post you’ll see Add due date to the right of each assignee. Tap that and choose a due date of today, tomorrow, a week from now or tap Custom to pick a date from a calendar view.
On the web
After you add assignees to your post you’ll see Set Due Date for All New Assignees at the top of the list of assignees, as well as Set Due Date next to each assignee name. Click into either to choose a due date.