What is bootstrap and what is its use as a framework?

There are several uses of Bootstrap as a framework since it offers design templates based on HTML and CSS technology covering the structure of a webpage and its visual and aural layout for various devices. Bootstrap also supports plugins for JavaScript and its design templates include variables like navigation, typography, tables, image carousels, buttons, forms, models and many more.

For Creating Layouts

Today, most developers prefer Bootstrap for creating layouts because it has a highly responsive CSS that sets easily across both mobile devices as well as desktop and laptop computers. When it comes to browsers, Bootstrap adjusts seamlessly with most of the popular ones like Google Chrome, Mozilla Firefox and Internet Explorer among others.

Effective Development Support

Bootstrap is an open source framework that has a large community which offers effective development support. It's easy to access Bootstrap experts via the ##bootstrap channel, Bootstrap Blog as well as Bootstrap Expo. The Bootstrap framework offers great resources made possible by excellent documentation - Bootstrap 3 Tutorial, Code Academy: Bootstrap and Web Design Tutorials: Bootstrap.

One essential advantage of this framework is that there are very few errors after you update the version you're currently using and that's because it has very good backward compatibility.

For more details check this easy tutorial https://www.tutorialspoint.com/bootstrap/