A job description is an internal document that clearly states the essential job requirements, job duties, responsibilities, and skills required to perform a specific role. A more detailed job description will cover how success is measured in the role so it can be used during performance evaluations. They are also known as a job specification, JD, and position description (job PD).
Of course, the job description should specify education, previous job experience, certifications and technical skills required for the role. You may also include soft skills, like communication and problem solving, as well as personality traits that you envision for a successful hire. While you may be tempted to list out every requirement you envision for your ideal hire, including too many qualifications and skills could dissuade potential candidates.