SMTP stands for Simple Mail Transfer Protocol, which is a standard commonly used to send an email.
From ServiceWorks you can send multiple notifications to your customers and employees. By default all the notifications are sent from email@example.com account. But if your customer needs to reply to your email and establish communication with you, you will need to configure your company email as the email sender.
Navigate to Settings -> Notifications -> template –> Personalized email notification. Add all the relevant information in here for your SMTP server and hit save.
Following are the ways you configure for different SMTP Providers.
Visit google support page for more details.
Visit Zoho support page for more details.