How to add a comment
If you've already signed a petition and want to add a comment, follow these steps while logged into your Change.org account:

Click on "My petitions" at the top of the page.
Select the "Signed" tab to view petitions you've supported.
Find and click on the petition you want to comment on.
Click the "Take the next step!" button.
On the next page, scroll down and click "Sorry, I can't do anything right now."
On the screen that says "Amplify your signature by adding your voice!", click the "Write a comment" button.
Type your comment and submit it.
You can also go directly to the petition’s actions page by visiting:
https://www.change.org/p/{petition-slug}/actions

If you’re not signed in or haven’t signed the petition yet, the site will prompt you to do so before allowing you to comment.