An essay or subjective answers can not be reviewed automatically by the system so you can grade them manually when students attempt them.
To grade essay type questions in the MeritHub quiz, follow the given steps:
Select the Quizzes/Tests option from the dashboard of a particular organization.
Under the Quizzes Section, select the appropriate quiz that contains the question to be graded.
Select the Attempts tab.
Click on the View Results option of the particular participant.
Select the pencil icon against the desired question and grade the participant accordingly.