Quite often dolls are completely sculpted from air-dry clays, but there are also a number of techniques used by cloth doll artists to enhance their creations. There are cloth-over-clay techniques and clay-over-cloth. In addition, many doll artists will create a cloth body that has a clay head (often with clay hands and feet also) .
These instructions from Rivkah Mizrahi show you how to make a cloth body look like it's sculpted from clay. She uses Creative Paperclay. See blog at Dollmakers Muse