In order to produce high-entropy alloys (HEAs), researchers have experimented with several processing strategies. HEAs may be produced in a variety of configurations, such as dense solid castings, powder metallurgy components, and films. The techniques for the synthesis of HEA may be grouped into three categories: melting and casting, powder metallurgy, and deposition techniques. These are the broad categories that can be used to describe the processing methods. Synthesis of HEAs by solid-state processing comprises mechanical alloying (MA) of the elemental blends, followed by consolidation. The MA process is a high-energy ball milling of the elemental powder mixes that involves the diffusion of species into each other in order to generate a homogenous alloy. The MA process is also referred to as the ball milling method. One of the benefits of MA is that it may provide great uniformity in the composition of the alloy, which is one of its advantages. In order to produce dense components, the HEAs that have been produced using the powder metallurgy process must be sintered. Conventional sintering of nanocrystalline alloy powders can result in considerable grain growth if the alloy powders are subjected to high temperatures for an extended length of time. In order to counteract this issue, the nanocrystalline alloys that are produced by MA are often sintered in spark plasma before being consolidated (SPS).