Notifications
Receiving notifications is fun, provided they are also valuable to you. Through the notifications tab, you can set what you want to receive and how you want to receive them. For example, if you have a link to Slack, you may want to receive everything here. But do you value your email inbox, then simply choose to receive them only there.
Do note you will need to install an (integrated) app first to be able to receive notifications.
Invoice notifications
Invoice is sent to everyone under the same organization and who has checked "Invoices" in profile notifications (as can be seen above). Invoices also go to the address set for that purpose. This can be found under billing in your organization settings.