Can we demand for additional component in a existing app?

Hi Tannu,

When you’re ready to add components to your app, you should first look at the out-of-the-box components that come with the framework. You can also leverage these components by extending them or using composition to add them to custom components that you’re building.

Components are encapsulated and their internals stay private, while their public shape is visible to consumers of the component. This strong separation gives component authors freedom to change the internal implementation details and insulates component consumers from those changes.

The public shape of a component is defined by the attributes that can be set and the events that interact with the component. The shape is essentially the API for developers to interact with the component. To design a new component, think about the attributes that you want to expose and the events that the component should initiate or respond to.

Once you have defined the shape of any new components, developers can work on the components in parallel. This is a useful approach if you have a team working on an app.

#To add a new custom component to your app you can see developer console

The Developer Console enables you to perform these functions.
Use the menu bar (1) to create or open these Lightning resources.
Application
Component
Interface
Event
Tokens
Use the workspace (2) to work on your Lightning resources.
Use the sidebar (3) to create or open client-side resources that are part of a specific component bundle.
Controller
Helper
Style
Documentation
Renderer
Design
SVG

#For more information refer to this link

Hope this will help you:

Thanks