You will four Fill options such as- Solid fill Gradient fill Picture or Texture fill Pattern fill At the end of these options, you will also see a check box for the Hide Background Graphics.

If you choose "Pattern," the Custom Pattern gallery becomes active so you can select your fill. Finally, choose "Content-Aware" to fill a selection with detail drawn from adjacent image areas.

To change the way a pattern fills an object, move the object to a different location on your artboard. Instead of defining your pattern with line segments, you also can use narrow rectangles ...