Difference between .com and .com.au
Domain refers to what you type in the address bar to find a website. Our domain is waterfallwaydesigns.com. We pay a registrar for use of this name, this license lasts a certain period, normally 1-2 years.
A domain extension is what comes after your name, .com, .net, .org.
.com - this is short for commerical and is the most commonly used extension for businesses on the web.
.net - this is network, this is normally used by companies that are involved in the internet infrastructure, like ISPs and domain registrars.
.org - this is organisation and the convention is to leave this for no-profit organisations.
There are many other less common ones, like .biz for small business, .mobi for mobile devices, .tv for television.
Then comes the country extension, like .com.au, this means a commercial business in australia. The difference here is that anyone can get a .com. To get a .com.au you need to be a registered business. You can qualify for these if you have an ABN, ACN, or BN. Having a .com.au is not necessary for all busnises and does pose an additional cost but it does have benefits. It legitimises your site, people know you have a business behind you. Search engines sometimes uses this in their search algorithm. In could result in better search results for you.
Waterfall Way Designs can advise you of available domains and obtain these as part of your package.