The podcast discusses various types of documentation for software projects, including documenting code and external documentation. It explores what should be documented within code comments versus other approaches like TypeScript. Maintaining outdated documentation is an issue, so validation through tests or expected errors is preferable. External documentation like readmes should link to other sources rather than include details likely to become outdated. Architectural decision records are recommended to explain important design choices. The discussion also covers establishing a domain language to reduce ambiguity and standardizing terminology between teams. Overall, the podcast emphasizes writing documentation that remains useful over time rather than just explaining code.