drupe features notes you can add to any of your contacts. The notes can appear whenever you get an incoming call from your contact and whenever you call them.
To create a note, drag your contact to the note icon. Once you're finished writing the text, tap done, or uncheck Show this during a phone call if you just want to keep that note to yourself and you don't want the note to appear during calls.
You can view all the notes you keep by tapping the notes action icon, edit any note by tapping on it, or delete it by tapping on the X to its right.