Simple and to the point, these plain IOU blanks can be used for all sorts. The design is black and white, with vector paint swashes on a white background. A plain white rectangle sits on top of the swashes. The word “IOU” is written in fixed text above and below the box. There are two designs (four total IOU cards per printable sheet). To use the IOU cards just print the PDF file at the end of this post and write down all the stuff you owe to people.