Hi @Skytulip ,
Thank you for getting in touch. I will start by saying that Shopify cannot provide direct advice when it comes to your tax liabilities, and that if you are unsure on what your obligations are, we would always recommend speaking to a tax or legal professional for guidance. Please bear this in mind as I offer some general advice below.
My understanding is that whether or not you are obligated to register for and remit taxes in the US depends on whether or not you are deemed to have a tax nexus in any state. It’s possible that if you have no physical presence in any state—no employees, offices, or warehouses, for example—then you will not be required to register for sales tax in any US state. However, these rules and definitions will very on a state-by-state basis, so whether or not you are required to register for sales tax may come down to which state your corporation is registered and based in.
I believe if you hired employees and opened a warehouse in the US then yes, you would most likely be deemed to have a tax nexus in the state in question and would be liable to charge and remit taxes in that state, although again, this varies on a state level. Please also be aware that states will typically have economic nexus rules, meaning you may be required to register for sales tax even without a physical presence in a state if your business meets certain economic thresholds (e.g. making a number of sales to customers in a state in a year).
I hope this has helped somewhat, but I nonetheless would encourage you to do your own research and consult with a professional if you are not confident in what your liabilities are from a taxes perspective.