Widgets/ gadgets are tools helps to enhance website or blog’s content and functions. Some widgets in Blogger are very helpful and serve the purpose of improving your blog.
Using Widget your blog visitors or readers can subscribe to your blog content , connect with you on social sites such as facebook, twitter, google+ etc, see most popular or recent posts. besides these blogger widget has many more function.
Steps to add a widget to Blogger.
Signin to your Blogger Dashboard.
Go to Layout page of your blog.then click on “Add a Gadget.”
Paste the code of the widget in the box that you want to add in your blog.
Adding a large number of widgets/gadget to your blog may reduce load speed i.e. your blog may load slower and take longer time.
So always use those widget which are really required and avoid using less important one.