If you are filling out your 15Five report and want an answer to only be visible only to you and your manager; you can make the answer private. Private answers will not appear for other viewers of your report, only your manager. Use the lock icon to the right of your answer to set it as private.
Not sure who can see your 15Fives? See this article.
How do I make an answer private?
1. Complete your response(s).
2. Click on the lock icon.
3. When the red lock appears, the answer has been locked.