Routing is just another way of fixing some content dynamically as part of your application.It is a key part of all websites and web applications in one way or another. 
It plays a central role in static HTML pages as well as in the most complex React web applications. Routing comes into play whenever you want to use a URL in your application.
Angular-UI-Router has stateProvider method which is used to create routes/states in application. State Provider takes state name and state configurations as parameters.
Syntax:
$stateProvider
.state('StateName', {
    url: 'Url pattern for this State',
    template: "Html content",
    controller: "Name of the Controller for this state"
});
Instead of template, templateUrl can be used and given the path of the HTML file to render for the state.
Example:
$stateProvider
.state('Home', {
    url: '/home',
    templateUrl: "home.html",
    controller: "HomeCtrl"
});