Adding fields to the comments for a content type

To add fields to the comment form for a given content type:

1. Navigate to the particular comment type associated with the content type you want to add fields to. (Administer > Structure > Comment types or http://example.com/admin/structure/comment)
2. Find the comment type for which you'd like to add fields on the comment form, and click "Manage fields" next to it.
3. Click the "Add Fields" button.
4. Select the type of field you want to add to the Comment type.
5. Enter a human-readable name for "Label" and click "Save and Continue".
6. Select "Allowed number of values" option as per your choice and click "Save Field Settings".
7. In the field settings, you have other options as Help text, Required field, and default value. You can fill in the options as per the requirement and click "Save Settings".