Talk to a certified accountant , and probably a lawyer, in USA with knowledge of Australia tax codes.
These are public forums with random people don't ever use such a place for the type of stuff that can put you in questionable legal territory.
Thanks for reaching out about this.
I understand that taxes are an important part of doing business, although when it comes to providing tax advice we aren't able to do so because of the legalities involved where taxes are concerned. So the best way forward is to consult with your local tax professional, or an accountant, so that you can verify if you'll need to charge taxes to your customers in Australia and overseas.
In saying this, we do have an introductory and general guide on US taxes here on our Help Centre if you'd like to gather a bit more information to begin with too.
When selling internationally, another thing to consider is the duties and import charges that your customers may need to pay for when ordering from your store. So this is also something that you can consult with your local tax professional too, just to ensure that you've covered all potential tax charges that is associated with selling globally.
If your tax professional has confirmed that you'll need to be collecting duties and import taxes in your checkout, you can install a third-party app from our Shopify app store to help you calculate these charges on checkout for your customer. It's a good idea to charge these fees to your customers on checkout, to avoid them in having to pay for additional charges when their order arrives. This will then help improve customer experience overall for your store too.
Let me know how you go with the information above! I'd be happy to help if you have any other questions.
Not providing you with tax advice but being from Australia can provide examples of how different companies operate and how they process orders to Australia. The local sales tax is called GST - Goods and Services Tax.
Lots of sites from overseas don't charge GST or don't show that a GST amount is being collected - you can test this out yourself by entering an Australian address and view the total. Having said that a lot of bigger companies have localised sites which don't add GST to total but display the GST amount the sale contains. So they therefore pay GST.
The main requirement to collect GST in Australia is similar for residents and non residents in that your sales have to be over AUD$75000 annually.