Hello Larisa,
There is discussion tab that can be used to added comments and discussion comments to a user story.
This link will provide you with more information.
https://docs.ca.com/en-us/ca-agile-central/saas/creating-user-story#create
Description | A Rich Text Format field for the description of your user story. Capture a brief description of your user story here. Enter any text in the description that will help all team members clearly understand the intent of the user story. |
Please let us know if you have any questions.
Thank you,
Christian