It depends on the specific social media platform. On many, like Facebook, there are privacy settings that let you control who can see your stories and sometimes even hide them completely. But the exact process varies from one platform to another.
Sure, you can hide stories on some platforms. Take Snapchat for instance, you can choose to hide your stories from certain friends or make them only visible for a limited time. Different apps have different features and ways to handle story visibility.
Yes, some social media platforms offer the option to hide stories. For example, on Instagram, you can usually do this through the settings.