You pick the apps. Instagram, TikTok, X, Facebook, Snapchat, Reddit, Threads, LinkedIn, Pinterest, Bluesky, whatever is actually on your phone. Anything you do not select is unaffected, which is what makes it workable to block feeds while leaving messaging and work apps open.
Blocking happens on the device, not on the platform. Nothing is deleted, deactivated or logged out. Your account, your posts, your DMs and your followers are untouched, and they are all still there when a session ends. If deleting accounts is what you were weighing up, we cover the alternative on blocking social media without deleting accounts.
It runs on Apple's own Screen Time frameworks. FamilyControls, ManagedSettings and DeviceActivity, the same sanctioned system Screen Time itself uses. No VPN, no profile, no workaround.