A job posting is an ad that employers use to announce their available job openings to potential job seekers. It essentially tells people about the job, what it entails, and what qualifications are needed to apply for it.
Job postings play a very important role in recruitment because they not only allow employers to connect with potential employees but also showcase their company values and culture, and make their hiring process easier.
For example, imagine that a certain Company is posting a job ad for a marketing role. The ad highlights the company's creative environment and the need for innovative thinkers for the marketing role. Candidates who happen to notice this and believe that their profile matches the qualities – values, and experience - of the ideal candidates that the job posting looks for, may be attracted to this and proceed to send their applications. This makes the hiring process rather straightforward for the company.