It is most probably cut from an A4 white printing paper

with a scissor or another sharp tool.

 

In the upper right corner, there is a brownish spot, most probably from coffee or tea.

 

It smells like the wallet - it must have been there for a long while but otherwise, no smell is traceable.

 

Its form still resembles the way it was folded in the wallet.

 

The letters are handwritten with a thin blue ballpoint pen, on the front side.

On the backside, letters are printed in 6pt, Arial fonts.