Apple store tax

Tax is collected wherever an iPhone is sold per the tax laws in every location. Your friend cannot order an iPhone from the US Online Store from outside the US. Apple doesn't ship internationally. And iPhone warranty is not international. And if you do purchase an iPhone 14 Pro in the US, you'd better ensure your cellular provider supports eSim as no iPhone 14 Model sold in the US comes with a physical sim card slot. All are dual eSim.

Whether you purchase from Apple online or Apple instore, tax will be collected. And again, if the doesn't have a US Address and Payment method, she can't order from the US online store. She might be able to walk into an Apple store in the US and purchased a phone, but tax will be collected.

I'm sure the 1099 you refer too is in your countries currency. The tax collected will be the tax for the county, city and state of the store the phone is purchased in and tax rates varies by municipality, so I can't tell you how much.

Also be advised iPhone 14 Pro is backordered in most locations, so there will be no guarantee the color, model and memory you seek will be just sitting in a store when your friend shows up.