To allow students to edit their responses after they submit a formative:
1. Click on "Assign"
2. Click on a class you've assigned to
3. Click on the toggle next to "Enable edits after final submission" so it turns green
4. Students will be able to edit and re-submit the formative as long as this setting is enabled or the formative is open:
Note: When you enable this setting, there is no limit to the number of edits a student can make.