Sensitive sections in a review that shouldn't be seen by the employee are marked with a padlock icon. It allows managers to share their screens during review meetings without the employee seeing the hidden section. It does not permanently change the visibility of a section.
For example, if feedback on your account is hidden from the employee, this section will be marked with a padlock. Similarly if you have any manager-only sections in your review form, like talent management, these will be also be marked. If you're currently sitting in the review meeting with the employee and they can see your screen, you may want to toggle on 'hide sensitive data' - this will hide all sections marked with a padlock.
Toggling it on/off does not impact what the employee can see on their side. For example, if feedback on your account is hidden from the employee, it will remain hidden whether you've toggled this on or not. It is simply a tool for managers to make use of if screen-sharing.
However, while adding your comments prior to the review meeting, it is advised that you leave this toggle off so you don't miss any manager-only sections in the review form. Some maybe mandatory and you won't be able to share your comments without completing them.
If you don't see any sections with a padlock next to them, this means that the review doesn't contain any sections that are hidden from the employee. In this case, enabling the 'hide sensitive data' toggle will not do anything.