The development team should tailor functionalities to each social application individually. That's why we encourage you to contact and estimate the project (it is for free). No doubt, whether you want to build a small community app based on interests, a comprehensive dating app, or a social media platform similar to Facebook or Instagram, you will need a matching algorithm that will connect users. You can specify the assumptions of this mechanism by yourself.
Here are the features that are necessary to run an attractive social app: login, profile, feed, messages or chat, searching/matching people, notifications, integrations with social media (like, e.g., Facebook, Instagram, LinkedIn), usage statistics, blocking users, and in many cases localization. One of the most important features (for app owners) are monetization solutions.