On the Applicant Profile, you can enter either an internal note (default), which is only visible among admissions staff, or you can directly notify the applicant & family via e-mail, if you wish to send a note to the parents. Click on the Notes tab below the applicant details. Notes are always internal by default.
Once you have entered the text for the Note, and are ready to send the Note, click to Add Note
When leaving an internal note, you have the option to CC one, or multiple, colleagues. The dropdown will show any admin users in your system. More users can be added at Settings > Staff Directory, if necessary.