What is NgModule?

NgModule is the main building block of an Angular application, represented as a class with the @NgModule decorator. It organizes the application into logical units and manages the dependencies between them.

The main functions of NgModule:

1. Declarations - a list of components, directives, and pipes that belong to this module.
2. Imports - connecting other modules to use their components, directives, or services.
3. Exports - specifies what from this module can be made available to other modules.
4. Providers - services available through dependency injection within the module.
5. Bootstrap - the root component from which the application starts (only in the root module).

NgModule lets you structure the application, manage dependencies, and reuse functionality across modules.