Adding a comment to manually scored activities

Hi everyone, I would be very grateful for a hint. In my Opigno 2 I need to provide the teacher an opportunity to comment a score - for example, the score is 8/10 and the teacher needs to explain the problem to a particular student. How can I add this feature? This relates only to the long answer & file upload questions, essays etc. - for questions with fixed answer, e.g. Multiple Choice, that's clear.