By default your website uses the Superia favicon for the website, however it is possible to overwrite this with a favicon of your own.
All you need to do is to upload your favicon into the file manager on your website, once you have done this then make a note of the folder where you have uploaded it, if you have not uploaded it into a folder then the internal link for your favicon will be /file-manager/favicon.ico. Just change favcion.ico for the name of your favicon.
Now all you need to do is to go to your template (Configuration > Templates), if you are using a system generated template then you will need to copy it first and make this the default template.
Edit the template and go to the advanced tab, then under advanced additional content add the following script to the head section;
<link rel="shortcut icon" href="/file-manager/favicon.ico" />
Just change /file-manager/favicon.ico to the intenral link for your file that you have uploaded and save your changes.
Some browsers take a while to pick up your new favicon and some of them will show it immediately, so don't panic if you can't see it straight away, sometimes pressing CTRL + F5 will force a refresh and force the browser to grab your new favicon.