You can add results only if a specific session was selected when enrolling a user in a course.
Otherwise, if the Participant selects the session option was chosen, there will be no option to add a result.
The result for Microsoft Teams and Zoom meetings are populated automatically under the Results tab and in the reports. However, you can change even an auto-populated result.
With regard to other trainings, aside from Microsoft Teams and Zoom meetings, their results should always be added manually.