Hi rani,
Modules
Modules are used in AngularJS to put logical boundaries in your application. Instead of coding everything into one application, you can build everything into separate modules to separate the functionality of your application.
For more details refer below links.
Module In Angular 2
Angular 2 - Modules
Components
Components are the logical piece of code for AngularJS application.
For more details refer below links.
Angular 2 - Components
Introduction to components
Angular 2 Components
Directive
Directive is a way to separate the re-usable function / feature.
A directive is a custom HTML element that is used to extend the power of HTML.
For more details refer below links.
Angular 2 - Directives
Angular2 - Directives