This guide provides an overview of devices, technology methods, and appropriate circuit configurations used as solutions in electric power systems for the purpose of mitigating power quality problems including voltage sags, harmonic distortion, voltage imbalance, and voltage fluctuations. This guide includes definitions, general need guidelines, performance objectives, electrical environments, input/output criteria, performance measurements, case studies, bibliography, economic assessment, and engineering trade-offs. The document addresses power quality assessment techniques from IEEE Std 1250-2018, which defines power quality terms and phenomena, and from IEEE Std 1159-2019, which provides a recommended practice for measuring power quality.