This document provides an introduction to dosage forms, which are the means by which drug molecules are delivered to sites of action within the body. It discusses the need for dosage forms due to challenges with direct clinical use of active drug substances. The document then classifies and describes various types of solid, liquid, semi-solid, inhaled, and parenteral dosage forms including tablets, capsules, solutions, suspensions, emulsions, ointments, creams, suppositories, injections and more. Excipients are also discussed as inactive ingredients that aid drug delivery without affecting therapeutic action.