Every admin takes notes about the actions they need to take on site, and Shield gives them the ability to do so.
Administrator Notes is a part of the Shield Security Dashboard. To access it, you just need to select "Security Dashboard" tab from the Shield's main menu => Notes.
This tool can be a powerful reminder to help you to plan activities on the site. Apart from that, every note you add will be recorded so you could go back and review them whenever you want.
Adding a note is very easy and you can add as many as you like.
Once you enter a note, you just hit the small "Add Note" button and it will be added. Shield will record the note itself, user name of the person who added it, and the exact time when the note was added.
Apart from this tool, the Security Dashboard also provides the other useful information. Read more about this here.