If you are looking to turn off the audible tone and vibration that occurs each time you attach or detach the S Pen from your Samsung Galaxy Note 5, here's a simple procedure to help you along.
Turn Off S Pen Sound and Vibration on Galaxy Note 5
To disable the S Pen sounds, simply go to Settings > S Pen > Additional Feedback. Clear the checkboxes next to S Pen sound and S Pen vibration feedback. The notification elements should now be disabled.