You can use automation with Zapier to save time when managing purchases and communicating with customers in online businesses. To start, ensure you have the right permissions in both PayPal and Mailchimp apps, and consider upgrading to a paid plan for premium features. Four ways to automate tasks include adding new customers to your mailing list after successful purchases, sending follow-up emails for refunds, organizing customers into segments for future email campaigns, and filtering by transaction type. You can create custom Zaps using these automation methods, exploring thousands of apps and workflows in Zapier's software.