 JD is nothing it's a job description of each and every profile which a company releases for every vacancy without a JD they cannot release any position and it just job description means the description of the vacancy that what skill set is required or what education is required this comprises of all of these things so for example if a vacancy is released by a company called XYZ for Salesforce admin so they will have the skill set experience and everything required in that particular JD or job description describing about what is the requirement for that particular position so they can include some customizations and technicalities which is included or required to be a Salesforce admin in their companies and it varies from company to company so it's very important to go through the job description of the position you are applying