Once a shop starts genuinely selling to international customers, VAT (value-added tax, common across the EU, UK, and many other countries) and cross-border tax questions come up in a way that most US-based sellers, in particular, don't initially expect. This is a plain-English starting point for understanding the basics, not a substitute for actual professional tax advice specific to your situation.
VAT is a consumption tax added at the point of sale in many countries outside the US, functioning somewhat similarly to US sales tax but applied more broadly and, in many regions, at a meaningfully higher rate. For a POD seller shipping internationally, the practical question is usually whether VAT gets collected by you at checkout, by your platform, or by customs upon import into the destination country.
A lot of this is actually handled automatically by the platforms themselves in practice — Etsy, for instance, generally collects and remits VAT automatically for sales to many countries with VAT regimes, meaning individual sellers often aren't directly responsible for manually calculating and remitting this themselves. This varies by specific platform and by the destination country's specific rules, so it's worth actually checking your specific platform's current documentation on this rather than assuming it works identically everywhere.
Where things can occasionally surprise a customer (and by extension, generate a support message to you): a package can sometimes be held at customs in the destination country with an additional import duty or VAT charge due on delivery, separate from anything already collected at checkout — this depends heavily on the destination country's specific rules and the item's declared value, and it's worth including a brief, honest note in your shipping policy that international customers may occasionally be responsible for customs charges depending on their country, so it doesn't come as a total surprise if it happens.
For anything beyond this general understanding — whether you personally need to register for VAT in a specific country based on your sales volume there, or how this interacts with your own domestic tax filing — this is genuinely worth a real conversation with an accountant familiar with cross-border e-commerce, since the specific thresholds and requirements vary by country and change periodically, making generic online advice a reasonable starting point but not a substitute for advice tailored to your actual situation.