Flannel is generally made with either a twill or percale weave. The fabric is then napped to hide the weave. Napping is a finishing technique that gives flannel that signature fluffy, fuzzy feel. Flannel can be napped on just one side, or it can be double-napped, meaning both sides of the fabric are napped, for extra softness. Flannel is also often sheared after napping for a smoother texture.

In the US and Canada, sheets are often sold in a four-piece set consisting of a fitted sheet, a flat sheet and two pillowcases. In China, a four-piece set consists of a duvet cover, two pillowcases and either a fitted or flat sheet. Fitted sheets are gaining popularity due to their ease of use. Use of good quality elastic make fitted sheets durable.