Fascia covers (also called fascia boards) protect the vertically-oriented edge of a roof. They run along the perimeter of the roof to guard the underlying rafters and top of the exterior wall from weather damage and animals/insects. These items also provide some aesthetic function. Fascia covers often serve as the install point for rain gutters, and may incorporate soffits to improve ventilation. The most common materials used for fascia covers are aluminum and vinyl.
Images credits: Roofline Solutions; Our Old Victorian