"The tichel (טיכעל), also called a mitpachat, is a headscarf worn by married Jewish women
in compliance with the code of modesty known as tzniut. Tichels can range from a very simple
plain color cotton square with a simple tie in the back to very elaborate fabrics with very complex ties
using multiple fabrics. As with any other form of clothing, it serves as fashion as well as its function of modesty." See the full description here.
Read up on head covering ideas here.