What is bias tape primarily used for?

Bias tape is primarily used to finish raw edges of fabric. It is a narrow strip of fabric that has been cut on the bias, which means it is cut diagonally across the grain of the fabric. This allows it to stretch and conform to the shape of the fabric edges it is applied to, such as armholes, necklines, or hems. The use of bias tape provides a neat, clean finish that prevents raw edges from fraying and enhances the overall appearance of the garment or sewing project.

In the context of the other options, creating pockets involves different sewing techniques and patterns that do not specifically require bias tape. Attaching zippers typically involves specialized processes and hardware, such as zipper feet, rather than bias tape. Similarly, adding weight to fabric is not the primary intention or function of bias tape, as it is meant for edging rather than modifying fabric weight.