Droplet microfluidics has evolved significantly over the past two decades, enabling precise and high-throughput manipulation of droplets across multiple disciplines, including materials science and biotechnology. This review discusses the physical mechanisms behind droplet generation and manipulation, summarizes their applications in droplet-derived materials and droplet-based biotechnology, and explores future directions for broader industrial and biomedical use. Droplet microfluidics allows for the isolation and precise control of samples in separate compartments, enabling high-precision analyses. The droplets, generated with uniform size and shape, provide a stable environment for biochemical reactions and can be used to synthesize functional materials with controlled release properties. In biotechnology, droplet microfluidics supports lab-on-a-chip applications, where droplets function as isolated reactors for high-precision and high-throughput analysis of multiple samples. Challenges remain in economically producing lower-value-added materials and precisely labeling droplet contents. The review also covers the physics of droplet generation, including the effects of flow rates, channel geometries, and fluid dynamics on droplet formation. Capillary and PDMS devices are commonly used for droplet generation, with PDMS devices offering high precision and flexibility. The review highlights the potential of droplet microfluidics in materials synthesis, including the creation of microparticles, microcapsules, and nanomaterials. It also discusses applications in biotechnology, such as single-cell sequencing and single-cell secretion analysis, where droplet microfluidics enables high-throughput and precise analysis of individual biological targets. The review concludes with a discussion on scaling up droplet generation for industrial applications and the challenges in achieving widespread use of droplet microfluidics.Droplet microfluidics has evolved significantly over the past two decades, enabling precise and high-throughput manipulation of droplets across multiple disciplines, including materials science and biotechnology. This review discusses the physical mechanisms behind droplet generation and manipulation, summarizes their applications in droplet-derived materials and droplet-based biotechnology, and explores future directions for broader industrial and biomedical use. Droplet microfluidics allows for the isolation and precise control of samples in separate compartments, enabling high-precision analyses. The droplets, generated with uniform size and shape, provide a stable environment for biochemical reactions and can be used to synthesize functional materials with controlled release properties. In biotechnology, droplet microfluidics supports lab-on-a-chip applications, where droplets function as isolated reactors for high-precision and high-throughput analysis of multiple samples. Challenges remain in economically producing lower-value-added materials and precisely labeling droplet contents. The review also covers the physics of droplet generation, including the effects of flow rates, channel geometries, and fluid dynamics on droplet formation. Capillary and PDMS devices are commonly used for droplet generation, with PDMS devices offering high precision and flexibility. The review highlights the potential of droplet microfluidics in materials synthesis, including the creation of microparticles, microcapsules, and nanomaterials. It also discusses applications in biotechnology, such as single-cell sequencing and single-cell secretion analysis, where droplet microfluidics enables high-throughput and precise analysis of individual biological targets. The review concludes with a discussion on scaling up droplet generation for industrial applications and the challenges in achieving widespread use of droplet microfluidics.