When creating marketing emails, businesses want people to read them and make a purchase. Customer.io is designed to help achieve this by sending targeted emails, push notifications, and SMS to lower churn, create stronger relationships, and drive subscriptions. It starts with customer data collection through various methods such as importing data or setting up JavaScript snippets on websites. The collected data can be used to segment audiences, trigger workflows, and automate marketing efforts. Customer.io also offers features like A/B testing for perfect emails and integrations with other apps via Zapier to further optimize email marketing results.