Settings has a Notification preferences screen where you tick how each update reaches you, per event, across four channels: Email, SMS, Push and In-app. Changes apply immediately, and SMS goes to your verified phone number.
A few things are fixed on purpose. Account, billing and safety messages are always sent; they show a lock in the list and carry no unsubscribe link. Everything else is yours to shape, and every such email has an unsubscribe link: one click turns off suggestion and reminder emails without signing in, and the link never expires.
Discreet notifications are on by default. Your lock screen hides who a push is from and shows a neutral "You have a new notification" instead; the in-app bell keeps the full wording. Overnight, 10pm to 8am in your own timezone, we hold push and SMS nudges and deliver them in the morning.