This article assumes that you have already submitted your assignment via Moodle's Assignment Activity, as described in these instructions. Here's how you can return to Moodle to see your instructor's feedback on your assignment:
If you scroll down on the page for the particular assignment, you’ll see a Feedback section. You should see the grade your instructor gave you for the assignment, any kind of summary comment s/he entered, and (possibly) an attached file with additional comments: