Is there a website that automatically insert citations?

There are quite a few MLA citation websites I have used that have worked out well.

One that I have used frequently is www.easybib.com. Not only does it make your citations, you can make all the citations you need and download them into a properly formatted document. It includes an extensive sources list and cites books quickly if you have the ISBN.

Just remember, when using a new citation website, double-check the citations. Not all sites are accurate.