There are two options that can be set in the Display Notes Selector feature under Preferences:

From "edit individual"—when this is checked, an index of notes will appear called "Notes List" when you access the notes screen while editing an individual.

While browsing—when this is checked, the Notes List will appear when you click on the "Notes Button" on the top menu bar, while the small pedigree chart is on the screen.

When you would want to use them will be explained below. You may check both boxes for both options to function.