This paper introduces the fundamental principles and classifications of optical frequency combs, reviews the generation mechanisms and representative architectures of electro-optic frequency combs (EOFCs), and systematically summarizes implementation approaches and performance characteristics of EOFCs on emerging material platforms, including thin-film lithium niobate (TFLN) and silicon nitride (SiN), covering schemes based on Mach-Zehnder modulators, phase modulators and micro-resonator modulator. Methods for spectral extension of EOFCs are discussed, followed by an overview of EOFC applications in spectroscopy, precision ranging, and optical communications. Finally, future development directions are outlined, emphasizing that interdisciplinary integration and co-design can further reduce control complexity, noise sensitivity, and thermal drift, while improving accuracy, environmental robustness, and frequency-stabilization performance, thereby accelerating the practical deployment of EOFCs in precision ranging and coherent communications.