Beaches are depositional landforms that form along coastlines where sand and shingle accumulate faster than they are removed by waves. Beaches represent accumulated material deposited between low and high tides. Beach material comes from cliff erosion, offshore sources, and rivers. Sand produces gently sloped beaches below 5 degrees, while shingle produces steeper beaches from 10-20 degrees. Factors like wave energy, type, and longshore drift influence beach profiles.