paper
Paper is a material that you write things on or wrap things in.
Bring a pencil and some paper.
You can refer to several sheets of paper with information on them as papers.
This filing cabinet is where we keep important papers.
Don't refer to a single sheet of paper as ‘a paper’. You refer to it as a sheet of paper or, if it is small, a piece of paper.
He wrote his name at the top of a blank sheet of paper.
The floor was covered in little pieces of paper.
A newspapers is often referred to as a paper.
Dad was reading the daily paper.
His picture was in the papers.