To use user secrets, you must first initialize your project. This adds a UserSecretsId to your .csproj file, which maps your project to a specific folder in your local user profile.
Once initialized, secrets are stored in a secrets.json file located in your user profile folder (e.g., %APPDATA%\Microsoft\UserSecrets\ on Windows or ~/.microsoft/usersecrets/ on macOS/Linux). How to manage user secrets in ASP.NET Core
The tool in ASP.NET Core provides a safe way to store this information during local development by keeping it outside your project directory. 1. Enable Secret Storage To use user secrets, you must first initialize your project