all depends on who is giving the exam.
going through a college means you will need to be proficient in a certain number of classes which adds up to "hours" with enough hours you will gain a certificate.
if it's an online course, all depends what that course goes into detail about.
autocad is massive so it's up to you how far down the rabbit hole you want to go. for most applications of autocad, you will not need to know everything about the program. learn what you need to do the task at hand, if you find interest in it. its a fun never ending learning curve.