An OMR sheet is used for multiple choice exams where answers are filled in with a #2 pencil and scanned by optical mark recognition software. There are four parts to an OMR sheet: the first and third are filled with pen, the second by the evaluator, and the fourth with pencil. Instructions specify only filling the required information like name and enrollment number with pen, and answers with pencil by filling entire bubbles for single answers without additional marks.