I recently created a HTML5 game locally on my PC. Then, I went to the Facebook developer website and created a new application but it asks you about the link to the application.
My application is local and I don't have any hosting website. I tried to upload it via jsfiddle, but they didn't accept it as a valid link. What should I do?
I suggest reading the Getting Started manual on Facebook Help Center, that will get you started very well. Make sure you follow the steps and search for more information there.
You are not able to use JS Fiddle for your Facebook application, you need to have some website to host the application in. There are several cheap (some free) web hosts, which you can use for hosting. It is always better if you can buy your own web domain and host, this way it's guaranteed that it will work.
When you have your domain set up, you create a folder for your application on the FTP server and use the address (e.g.
https://example.com/myapp/) and place that address into the Canvas URL field on the configuration panel in Facebook Developers site.
The steps on how to continue from now on can be found from the manual linked above. Hopefully this helped you out!