From what I know you can get the sales tax return (the stamp in your passport) only on the same day you purchase the item. In this case which day would that be, the day I place an order and pay for an item or the day when I pick it up ?
Thanks for your help guys.
There's no physical stamp in your passport.
If you buy something in a store which offers tax back they will either:
a) calculate the cost of the goods before tax, and charge you for that
b) charge you the full price, and then you have to take your goods and receipt to another counter to reclaim the tax
In either case, what the store is supposed to do is staple/attach the receipt to the passport. When you leave the country, you are supposed to submit the receipts to prove that you are actually taking the goods you bought tax free with you out of the country and haven't passed them off to someone in Japan. However, speaking of myself (a resident) and friends and relatives, we've never been asked for them or been checked.
I think you're confused about the meaning of stamp. Perhaps you mean entry stamp in your passport to prove that you're a visitor and not a resident.
https://tax-freeshop.jnto.go.jp/docs/Taxfree-Shopping-Guide.pdf
It's not uncommon for people to buy things like snack food tax free in Japan and then consume the lot whilst in Japan. If you ever get asked about the food if you have to present your receipts, you could always say they're in your checked luggage if you get asked after checking in. I have never had to open up a suitcase before check in.
If you're worried, give one of the Apple stores in Tokyo a call and explain your situation. They have English speakers.
Alternatively, instead of buying from an Apple Store, go to one of the big electrical stores, like Yodobashi or Biccamera. They have official Apple concessions there, and will usually have stock of machines with US keyboards, as do the Apple Stores. If you want a UK keyboard or custom configuration, then it's best to get in contact with an Apple Store in advance so they can order one in. I asked once years ago and I think they said it would take a week or so.
*Tax refunds can no longer be done at airports in Japan