Brand identity means that one given from business to customer to expect certain things. That expectation involves service, product quality etc. Achieving a strong brand is really tough.
Logo design, custom brochure design, flyer designing (rack cards), Letter heads, Envelopes, Business cards etc includes in brand identity. Corporate as well as small companies need brand identity designs.
Brand identity design gives visual identity to your company. A brand designer is to make sure the brand remains fresh and effective.