It's just a tileable (or repeatable) background, made from simple line art. It has no special name.
This is really a very broad question, so I can only give a very broad answer.
If you are asking how to draw simple shapes in Photoshop, have you tried using the Pen tool or the Shape tools to make simple graphics? You can apply a simple stroke to a shape in Photoshop. If you don't know how, there are tutorials online that show you how to use the Pen tool in Photoshop.
Photoshop is not really the ideal software for this kind of thing, but it would do at a push. It would be easier to use vector image editing software such as Adobe Illustrator or even the free software Inkscape(dot)org.