Alerts center
Web: /notifications. Mobile: Notifications screen.
Read/unread, delete, mark all read, delete all, tap through to the related profile, post, or follow request.
Preferences (instant save)
Settings → Notifications.
Social: new follower, DMs, comments, mentions, likes, reactions, follow requests.
Defaults are on. Alerts are in-app only today — no mobile push or web push yet.