Electromagnetic modeling is a critical analysis and design methodology in various fields such as radio‐frequency (RF) and microwave engineering, antennas, radar, remote sensing, medical diagnostics, bio‐electromagnetics, physics and radio astronomy, and electromagnetic compatibility (EMC) and interference. It formulates and solves electromagnetic field problems using mathematical, physical, or computational models that relate the electromagnetic functionality of devices to their geometrical and material parameters or predict how electromagnetic fields interact with physical objects and materials. This chapter presents the most common methods for modeling electromagnetic scenarios in the frequency, the spectral, and the time domain, as well as their hybrid combinations. They are introduced as projective approximations of field solutions using the method of weighted residuals (MWR). This unified perspective best illustrates their properties, differences, and their suitability for solving a particular electromagnetic problem, thus helping the reader to appreciate the connections, similarities, and differences among the various methods. It also reflects historical and methodological developments and aims to provide a foundational understanding of current electromagnetic modeling methods.