When you create angular application , initial folder structure will look like below.

 

Important files and their use

.editorconfigConfiguration for code editors.
.gitignoreSpecifies intentionally untracked files that Git should ignore.
README.mdIntroductory documentation for the root application.
angular.jsonCLI configuration defaults for all projects in the workspace, including configuration options for build, serve, and test tools that the CLI uses, such as Karma, and Protractor.
package.jsonConfigures npm package dependencies that are available to all projects in the workspace. See npm documentation for the specific format and contents of this file.
package-lock.jsonProvides version information for all packages installed into node_modules by the npm client. See npm documentation for details. If you use the yarn client, this file will be yarn.lock instead.
src/Source files for the root-level application project.
node_modules/Provides npm packages to the entire workspace. Workspace-wide node_modules dependencies are visible to all projects.
tsconfig.jsonThe base TypeScript configuration for projects in the workspace. All other configuration files inherit from this base file. 

 

Files and Folders in src\

app/Contains the component files in which your application logic and data are defined. See details below.
assets/Contains image and other asset files to be copied as-is when you build your application.
environments/Contains build configuration options for particular target environments. By default there is an unnamed standard development environment and a production ("prod") environment. You can define additional target environment configurations.
favicon.icoAn icon to use for this application in the bookmark bar.
index.htmlThe main HTML page that is served when someone visits your site. The CLI automatically adds all JavaScript and CSS files when building your app, so you typically don't need to add any <script> or <link> tags here manually.
main.tsThe main entry point for your application. Compiles the application with the JIT compiler and bootstraps the application's root module (AppModule) to run in the browser. You can also use the AOT compiler without changing any code by appending the --aot flag to the CLI build and serve commands.
polyfills.tsProvides polyfill scripts for browser support.
styles.sassLists CSS files that supply styles for a project. The extension reflects the style preprocessor you have configured for the project.
test.tsThe main entry point for your unit tests, with some Angular-specific configuration. You don't typically need to edit this file.

 

Files in app\

app/app.component.tsDefines the logic for the application's root component, named AppComponent. The view associated with this root component becomes the root of the view hierarchy as you add components and services to your application.
app/app.component.htmlDefines the HTML template associated with the root AppComponent.
app/app.component.cssDefines the base CSS stylesheet for the root AppComponent.
app/app.component.spec.tsDefines a unit test for the root AppComponent.
app/app.module.tsDefines the root module, named AppModule, that tells Angular how to assemble the application. Initially declares only the AppComponent. As you add more components to the app, they must be declared here.

 

Next : Angular CLI Commands