Selecting information about entities for display to drive interactions on online systems

An online system selects information about entities for display to viewing users based on the relevance of the information to the viewing users. The online system maintains information describing one or more third parties. The online system receives a request from a client device to provide a content item of a third party for display to a viewing user. Responsive to the request, the online system accesses information describing the third party and selects a subset of information based on a likelihood that the viewing user will interact with the content item based on the subset of information. The online system generates a content item including the selected subset of information and an element selectable to initiate an interaction with the third party and provides the generated content item to the client device for display to the viewing user.