Sheds cost an arm and a leg.

I am thinking digging a hole on my property to store certain
material underground. Do I need governmental permission to dig (I live
Oklahoma) half a garage size large and deep hole?

Some of the stuff that I want to store are lots of books and papers.
They could rott when I just put them in the ground, cover them with a
blanket and throw dirt over it. What material could I use to wrap
around to
protect the books and papers to protect the books and papers?