You can use Annotations to leave feedback on your students' work. Annotations can be added on projects and team repls. Annotations provide an easy way to give feedback on a specific line of code.
You can add an annotation to a repl by left-clicking on the specific line number where you want to leave the comment. A floating "annotate" button will appear by the line number. Left click on this button.
Alternatively, right-click anywhere on the line of code you want to comment on, and choose "Annotate" from the menu that appears.
A comment box will pop up towards the right of the code. Type in a comment and press the arrow on the right to save it.
The student who created the repl will receive an in-app notification as well as an email with your comment. They'll be able to reply to the comment or modify the code accordingly.