Postmark's inbound parsing service can parse emails into a structured JSON format, allowing developers to easily access and utilize the data contained within. This process removes complexity from manual email processing, making it easier to integrate with applications and databases. Inbound parsing can be applied to both structured and unstructured emails, providing a flexible solution for various use cases such as order confirmations, new replies to messages, form submissions, promotional emails, and more. To start using Postmark's inbound parsing service, developers must set up an inbound webhook, which involves configuring an inbound email address and URL that will receive the parsed JSON data. Once configured, developers can test the endpoint with example emails and use the parsed data in their applications or databases. Additional resources are available to help get started with inbound message processing using Postmark's service.