The Notifications tab is where you can update the notification settings for your account.  You can decide how you can receive notifications for certain system events here, such as event reminders, when a new lead arrives, etc and how it arrives via email, sms or both.

To access Notifications, click on your name in the top-right corner of your dashboard, then click “My Profile”. 

Next, click on the Notifications tab.

To opt-in to receive notifications, check the box next to the applicable situation under Email and/or SMS. You can also opt-out of notifications by unchecking the boxes.  Remember to click save when you're done.