Microsoft released a new build of Windows 10 to Insiders in the Dev channel today, and as we've seen in recent weeks, it was a pretty uneventful release. However, the company did announce a new feature for Cortana alongside the new build, but you can use it even if you're not in the Insider program.
The feature is a new File skill for the digital assistant, which means it can now help users find and open documents without navigating their files manually. Users can ask Cortana to open a specific file using parts of its name, using the author's name, file type, or simply files that were accessed recently.
For users signed in with a personal Microsoft account, the feature can only search for files saved locally on the PC. Business users, on the other hand, can use it to open files from SharePoint and OneDrive for Business, in addition to locally-stored files.
Based on our testing, the feature is working at least on Windows 10 version 20H2, so you don't need to be an Insider at all. However, you do need to have the Cortana language set to English and the region set to the United States.