In Angular, there is a distinction between adding styles and scripts in the `angular.json` configuration file and adding them directly in the `index.html` file. Here's a breakdown of the key differences: 1. `angular.json`: The `angular.json` file is the configuration file for an Angular project. It contains various settings and options related to the project's build process, including the configuration for styles and scripts. In the `angular.json` file, you can specify the styles and scripts that should be included as part of the project build process. The styles are typically specified using the `"styles"` property, which accepts an array of file paths for CSS or Sass files. The scripts are typically specified using the `"scripts"` property, which accepts an array of file paths for JavaScript or TypeScript files. These styles and scripts defined in the `angular.json` file will be automatically included and bundled as part of the build process. They will be loaded and applied to the application during runtime. 2. `index.html`: The `index.html` file is the main HTML file for an Angular application. It is the entry point for the application and contains the basic structure of the HTML document. In the `index.html` file, you can add external stylesheets or scripts directly using `<link>` and `<script>` tags. These tags reference external CSS or JavaScript files hosted on a server or included from a CDN. By including them in the `index.html` file, they will be loaded by the browser when the application is accessed. The styles and scripts added directly in the `index.html` file are separate from the ones specified in the `angular.json` file. They are not part of the build process or bundling performed by Angular. Instead, they are loaded and applied by the browser directly when the `index.html` file is loaded. In summary, the key differences are: - Styles and scripts specified in the `angular.json` file are part of the Angular build process and bundled with the application during build time. - Styles and scripts added directly in the `index.html` file are loaded by the browser at runtime, separate from the Angular build process. Typically, it is recommended to use the `angular.json` file for including styles and scripts that are part of the project and managed by Angular. On the other hand, adding external stylesheets or scripts in the `index.html` file is useful for including third-party libraries or custom styles and scripts that are not managed by Angular.