paper

PAPER

thin flat material which is made from crushed wood or cloth and is used for writing, printing or drawing on

       look good on paper

to seem fine in theory, but not perhaps in practice; to appear to be a good plan

he plan looks good on paper, but it may not work.

not worth the paper it's written on 

 meaningless or without authority; of no value.

 That contract isn't worth the paper it's written on. 

envelope- a flat, usually square or rectangular, paper container for a letter.

Wrapping paper- Decorated paper which is used to cover presents.

Cigarette paper- a thin piece of paper used in making a cigarette, especially by someone who makes their own.

Tissue- soft paper which is used for cleaning, especially your nose, and is thrown away after use.