Once the package arrives in your country, you will be contacted by your postal service to pay any duties owed, and then receive your product according to your postal service's usual process
Instead, use oversized sleeves like the KMC Character Guard or the new Dragon Shield Clear Outer (ignore the name) which will both fit over your standard outer sleeve
Deck boxes are fairly self-explanatory: They help you get your decks from point A to point B safely
The card is also more than viable in lower brackets, however, as a non-Game Changer alternative to Force of Will
That's a pretty hefty tax in most decks, and you'll probably need some white mana ramp cards to help pay for it
These are not going to be Standard-, Pioneer-, or Modern-legal cards, but are legal in Eternal formats (Legacy, Vintage, Pauper and Commander)