Support fabrics are hidden construction elements that maintain a garment's shape and comfort. They include interfacing/interlining, underlining, and lining. Interfacing/interlining is used to strengthen areas with fasteners. Underlining gives support and opacity. Lining finishes the inside, improves comfort and durability. Fabric choices depend on the fashion fabric's weight/care and the garment type/style. Lining and underlining should be lighter weight and softer than the fashion fabric. Support fabrics are essential hidden elements for maintaining garment structure and performance.