A junction object is a custom object with two master-detail relationships that allows you to create many-to-many relationships between two objects. In this case, the Job Application object can be used as a junction object to link the Application object and the Job Posting object, so that each application can be related to one or more job postings, and each job posting can have one or more applications. References: https://help.salesforce.com/s/articleView?id=sf.relationships_manytomany.htm &type=5