Essay questions are designed to allow you to give a manually graded question on Quest assignments. These questions can be graded within Quest or have grades uploaded as described here: Importing Student Grades. Grades for assignments with essay questions will not be shown until the grades for the manually graded questions are provided.
Once you have finished filling in the content of the question, you will have to save the draft by clicking the button at the bottom of the page.
After you are finished editing publish the question for use on assignments.