The hemp plant and the cannabis plant are basically the same plant, with the difference lying in the percentage of THC by weight. Hemp, as defined in the U.S. today, is meant as a legal term to describe cannabis plants with less than .3% THC, which is a negligible amount and will not get you high. Hemp is used for many other purposes, including harvesting CBD.
The passing of the Agricultural Improvement Act of 2018, also known as the 2018 Farm Bill, ended the prohibition on hemp, removing it from the Schedule I list of controlled substances and eliminating enforcement by the DEA. The farm bill makes hemp production and distribution legal under federal law and establishes a framework of shared oversight by tribal, state, and federal authorities.
Hemp farming has increased since the passing of the 2018 Farm Bill, and the hemp plant is now used to extract CBD, Delta-8, and other novel cannabinoids. Hemp plants are used for many other purposes, such as hemp seeds for food, and hemp stalks used for fiber and materials referred to as industrial hemp.