modern hand-made paper

In the sentence:‘The raw materials used for modern hand-made paper are cotton and linen rags.’
-What does ‘modern hand-made paper’ mean?
-What does ‘linen rags’ mean?
Thank you !

Paper that is made by hand (rather than manufactured on a machine) in modern times.
Linen is a type of cotton. A rag is a scrap piece of cloth, often torn from a larger piece of fabric. Linnen rags = Cotton scraps of material.