Should you use a comma before the "Inc." in a company name?
Xona Games, Inc.
Xona Games Inc. (in this example, this is the official registration format)
One should write the name of a company exactly as it was spelled (or misspelled) in the official registration.
It depends on the style guide you follow. There are lots of guides and they differ on many things. The Chicago Manual of Style says "no". However, if it's your company, do what you want. The style guides don't dictate how you should label your business. Just be consistent.
Page 134 from the Associated Press Stylebook 2013 reads, "Do not set off with commas".
Sorry, the law is strict on this. If the comma appears in the papers of incorporation, it must be used in all legal transactions. Many lawsuits have been lost because the person or company filing suit left out the comma, or inserted it, against what was filed. Any attorney will explain this for you. I once had to fire a proofreader at my publishing company because he insisted on inserting the comma where it wasn't called for, even though I explained the law to him.