There are a few options for obtaining a zip code database:
1. You can purchase a zip code database from a data provider. There are many companies that sell zip code databases, often with additional demographic data included.
2. You can use a free zip code database. While these may not be as comprehensive or up-to-date as paid databases, they can still be useful
3. You can use an API to look up zip codes and retrieve information about them. It allows you to look up zip codes and retrieve information such as the city, state, latitude, and longitude for a given zip code.
4. You can scrape a website that lists zip codes and their associated information.

https://www.datalistsgroup.com/zip-code-mailing-list