I searched for an answer to this problem and couldn't seem to find much - on my initial checkout page, Shopify is autofilling my home state, automatically adding tax to the subtotal. Here's the problem: I only charge tax for my home state, so if you're in the 49 other states, this tax doesn't apply to the customer. I feel like seeing this tax is scaring some potential customers off before they fill their actual address to see that they don't have to pay tax.
Is there a way to not autofill this at checkout so tax doesn't automatically add to the subtotal? Of course, once the customer puts their actual address in, the correct tax amount will show - I just don't want to automatically add it if it doesn't apply to the customer. (And I've tried to clear cookies/cache and use incognito windows - it does it regardless of history or location.)
This is Dallas from the Shopify Social Care Team.
When it comes to the checkout there isn't actually a way to make any customizations since the checkout is a locked sheet of code. You're not able to customize it, but I'm not able to either.
If you're worried about the taxes being added on you might want to look at adding the taxes into the price of the products. By the sounds of it, you're in the USA so it isn't as common in North America, but that is very common in places like Europe. If you're going to think about doing that you're certainly going to want to talk with a local tax professional to see if that's something that could be looked into for your business.
This way the prices will be a little higher, but there won't be a line showing the taxes that will be added on. It might not seem like much, but that can work to make some customers feel more comfortable with the prices.
If you do decide that you want to do that you can just go to the Settings in your Store Admin and click Taxes > Show all Prices Included.
For what you're wanting that will be the best option. Make sure you talk with a local tax professional though if you do this.