It isn't possible to edit the source code of your website. There are specific areas of the Sitebuilder to add tags for SEO and Google Webmaster, here are links with more information:
Articles in this section
- How do I make a one page website?
- Do I need to be computer savvy to create a website?
- How can I create a good looking website?
- Can I edit my site from another computer?
- Is there a time limit on finishing the site?
- How long does it take to setup a Yola website?
- How do I edit my source code?
- Learning the basics of a good website design
- Changing the name of your website
- Planning to create a website