You can comment and read comments on an Issue by scrolling down to the Comment section.
You can format text in the comments.
Comments can also be added to Issues by replying to their email notifications. The body of the email will be added to the Issue as a comment.
Adding comments via email is possible under the following conditions:
- if you reply to an email notifying you of when the issue or comment are added.
- the sender's email address is one of the registered members of the project.
- the sender, one of the project members, has their settings set to "receive emails".
However, even if all conditions are met, some email applications will not be able to post the comment to Backlog.