The robots file is auto-generated and not something you're able to edit.
As of today, June 21st, 2021, we have launched the ability to edit the robot.txt file to give merchants more control over the information that is crawled by search engines. You can learn more about how to edit your robot.txt file through our community post here.
Due to the age of the topic, I will be locking this thread. If you have any questions about the new feature, please do not hesitate to create a new post under our "Techincal QA" board.