Can you let us know what you want to use the Due Date field for? Are you trying to set Due Date as Target End?
Have a look here at the new feature in Server that would allow you to do that:
If you're using Cloud then this is not yet a feature, but you can vote on it to show your interest and comment with your usage case!
Hi All! We’re excited to share the launch of an announcement banner that lets Jira site administrators communicate directly to their users across their Jira Cloud instance. ...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events