As you work through your plan, you might have questions for the person working on a task. You can add a comment to the task to start a discussion. Why isn't this working for me?
Note: You will not be able to add comments to tasks in plans that are created by Connected Yammer Groups.
To add a comment, select a task to bring up its details, and then use the Comments box to discuss things with your team.
After a comment is added, the task shows a comment symbol to give the team a heads-up that there's something new to read.
Comments are shown in the task with the most recent comment at the top.
For Office 365 Groups in Outlook, you can also take a look at all conversations going on for all tasks in your plan. Select the three dots below your plan's name, and then choose Conversations. From there, you can see comments for all of the plan's tasks in Outlook on the web. You can also use the Outlook Groups app to view conversations about your plan. Learn more about conversations in Office 365 Groups in Outlook.