The tax will be charged by the state of the recipient. As for logistics, get real, this is the computer age.
I used to work with the tax department of a large national company. Sales tax laws were a nightmare. Sometimes they apply to a single piece of property.
Pretty trivial to calculate all taxes given the zip code.
Sales taxes can vary a great deal within a state, city, township, county etc. can tack on their amount.
It’s not just where the purchaser lives. It’s what is being sold. Good example in the article - a Snickers bar is a different tax rate than a Twix bar because the Snickers has flour in it. Take a look at any state’s Dept of Revenue website and you will see that sales tax laws are extremely complicated. If you are a big company you can buy an expensive software package that will get it mostly right, but even those don’t work 100%. I used to work at a large company with sales in over 40 states, and we had sales tax audits all the time, by various different states. They would always find something. Trust me - it WILL be a nightmare, unless they come up with some simplified rules that all the states can agree on.