Fiber content is the primary classification driver for most fabric HTS headings: the chief weight or chief value of fiber (cotton, man-made, wool, etc.) typically determines the applicable chapter and duty rate. Importers must obtain mill certificates or lab test results confirming fiber composition before entry to avoid misclassification penalties.

Standard entry documentation includes a commercial invoice with fiber content by weight, country of origin, fabric width, and construction details (woven, knit, nonwoven). Textile and apparel imports also require a visa or export license from certain countries under bilateral agreements, and CBP may request laboratory analysis to verify declared fiber content.