I think for digital services the VAT or sales tax is usually based on the buyer’s location, not the seller’s. Other types of sales can follow different rules but I’m not a tax expert.
In practice the seller is responsible for collecting and sending the correct tax where required. In short, we charge VAT or sales tax based on the buyer’s location, not ours. That’s also what you should be doing if you’re selling direct, although the thresholds vary by region. This is why many developers use services like Paddle or Fastspring since they handle all of it.