Windows default apps determine which program opens a file when you use its normal opening action. If text documents repeatedly open in an inconvenient app, you can change the association for that type.
Choose a file extension
Open Settings, then Apps and Default apps. Search for the extension you want to change, such as .txt. Select the result and choose an available app.
You can also select an application to review the file and link types it can open, then change an individual association. Start with the specific type that is causing the problem instead of changing every available association.
Test a harmless sample
Use a document you can safely open and inspect. Confirm that it launches in the chosen app and that the contents display as expected. Opening a text file successfully is a more useful check than merely seeing the app name in Settings.
Keep the original file while testing. If you save an edited copy, use a distinct name until you understand how the application handles the format.
Separate opening from conversion
Choosing a different default tells Windows which app should handle the file. It does not by itself turn the document into another format. If you need a PDF or another output type, handle that conversion through an appropriate export or save operation.
- Check the extension you are changing.
- Use an app that supports the actual file type.
- Review the result with a sample document.
- Return to Default apps if the choice is inconvenient.
A targeted association change keeps troubleshooting manageable. Once one type behaves correctly, decide separately whether any other file types need the same treatment.
Official reference: Read the official instructions.
Featured image: conceptual illustration, not a device screenshot.