The ability to add your own notes to an individual lead record is included within the Details tab.
If you scroll down the page, you will find a field below the Recent Activity section in which you may add your own notes to the lead. Click the paperclip icon to attach a file to the note. Click the blue button to save the note.
When adding a note to an individual lead record, you may tag another user by typing “@” and then entering first or last name to search for the user. Users who match what you are typing will appear in the list above for you to select.
You also have the option to upload an image via the attach file option to appear along with the note.