Yes, when the option is enabled, your clients can easily add notes to their favorite images.
Setting it Up
Favorite notes are enabled through a Gallery Type setting. To update the setting, do the following:
Navigate to Photos » Gallery Types.
Click on the name of the gallery type that you'd like to enable the setting on.
Scroll down to the "Allow Favorites Notes" setting, found within the "GALLERY OPTIONS" section.
Place a checkmark in the box to enable the option, or remove the checkmark to disable it.
Save your changes.
Client View
Once the setting has been enabled, your clients will be able to add notes to their favorites by clicking the notes icon associated with any image previously marked as a favorite.
Photographer View
You can view the favorites that your clients have selected, along with any notes that have been added to them, by doing the following:
Navigate to Photos » Galleries.
Find the gallery that you'd like to view the notes for.
Expand the Visitors menu and select the "View Visitor Favorites" option.
Additionally, any recent notes will also be displayed within your Dashboard, similar to the following: