Low temperature or flat dry
From my own experience: you should expect some shrinkage according to the fabric:
cotton: about 5% in length, about 2% in width
polyester: none
rayon: 5% to 10%
acrylic: about 5%
linen: DO NOT wash, dry clean only
silk: DO NOT wash, dry clean only
wool (including cashmere): DO NOT wash, dry clean only