You will only see the option to submit an exam after answering all of the questions in your exam. If you have gotten to the last question of an exam and still do not see the "End Exam" icon, the exam likely contains at least one question without a recorded answer.
If there are unanswered questions within the exam, their corresponding question numbers will remain orange in the Performance settings panel on the right side of the browser. Clicking the question number will navigate you directly to that question, so you can quickly answer skipped questions. You can also click the "Unanswered" toggle switch, and the program will only show you the question numbers which are unanswered.
Once all questions have been answered, the “End Exam” button will appear!
If you wish to stop an exam before an exam is complete, you may select the “Pause” button. Paused exams will save to the Incomplete Exams tab of the Practice Exams section. Paused exams can be resumed from there.