Plasmid vectors remain central to gene editing and genetic engineering, providing flexible, modular, and cost-effective platforms for genome manipulation across microbial, plant, and eukaryotic systems. Continuous advances in synthetic biology, metabolic engineering, and CRISPR–Cas technologies have driven significant evolution in plasmid design, emphasizing precision, stability, and host adaptability. Modern plasmid vectors integrate optimized origins of replication, regulatory elements, selectable markers, and programmable editing modules to support diverse applications ranging from functional genomics to industrial bioproduction. Despite their widespread adoption, plasmid-based systems face inherent challenges, including metabolic burden, structural instability, off-target activity, and regulatory constraints. This review systematically examines the design principles governing plasmid vectors, evaluates their efficiency in gene editing workflows, and highlights their applications across biological domains. Particular attention is given to CRISPR-compatible plasmids, broad-host-range vectors, and advanced architectures supporting base and prime editing. By synthesizing recent evidence from microbial, agricultural, and biotechnological studies, this review provides a comprehensive framework for rational plasmid vector selection and future optimization strategies in gene editing and genetic engineering.