Which type of gland has ducts and empties its secretion onto an internal or external surface?

The type of gland that has ducts and empties its secretion onto an internal or external surface is called an exocrine gland.

Exocrine glands are distinguished from endocrine glands, which release their secretions directly into the bloodstream rather than through ducts. Examples of exocrine glands include salivary glands, sweat glands, and the pancreas (which has both endocrine and exocrine functions). Exocrine glands play essential roles in various physiological processes, including digestion, temperature regulation, and lubrication of surfaces. The ducts of these glands allow their secretions, such as enzymes, sweat, or mucus, to reach specific target areas either on the surface of the body or within internal organs.