Paper required to make the article longer (3)
I believe the answer is:
pad
'paper' is the definition.
(I know that pad is a type of paper)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for pad that I've seen before include "Absorbent material" , "Bachelor's place?" , "Stuff the animal's foot" , "Walk softly around the apartment?" , "Batsman's protection" .)