Students cannot make corrections after submitting, even if you return their submission to them. You'll have to first Re-Open or Reset their submission.  Re-opening retains their work and let's them continue working. When they're finished, they'll submit it again. Resetting a student's submission erases their work and lets the student start over. In both cases, your annotations to their submission will be retained.

Let's take a look at each!

How To Re-Open a Student's Work

Once a student submits their work, you have the options to Reopen the assignment for them. This action allows them to continue working on their assignment - all of their previous work will still be there. 

You also have the option to show your students their missing and incorrect answers when you reopen the assignment. This allows them to know which questions they need to correct or finish!

How to Allow a Student to Check Their Answers Without Submitting

If you want the students to be in charge of their own practice, you can set an assignment option that lets them check their answers as they're doing the work. You can even control how many times they're allowed to do that.

You'll find this option on the final step of creating an assignment.

You have several preset options and can even set a custom value. The preset options are:

Once your students begin to work on an assignment with this option set to anything other than "No," they'll see a button that lets them check their answers. Clicking that button will give them immediate feedback on where they have incorrect answers. There's even a convenient counter and navigation aide in the upper right. Just have them click those left and right arrows to go back and forth between the incorrect answers.

Once they arrive at an incorrect answer, they can simply answer it again and the question will hide the feedback unless the student uses the "Check My Answers" button again.