Probably the most common method is to convert fibers into yarns, which are then constructed into fabrics. Yarns are essential for knitted, woven or knotted structures and for many braided ones. Yarn is defined by the American Society for Testing and Materials (ASTM) as A generic term for a continuous strand of textile fiber, filament, or material suitable for knitting, weaving to form a textile fabric. Yarn occurs in the following forms.

b. Loops: There are two types of loop. They are Thread loop and Fabric loop. The thread loop is an inconspicuous fastening which is most often found at the neck edge. To make a thread loop, sew four or five strands of matching thread on the under lap in the correct position, then work buttonhole stitches over these strands.