There are a number of physical formats you can consider when buying platinum:
If you're not buying an huge amount of platinum, you should aim to maintain direct control over it at your home or other property.
If you're investing heavily, to the point where you need a safe alternative location to store it, be sure to go somewhere like Switzerland with strong property rights. It's key to make sure they can't lend or hedge using your stash.
The Swiss government is unique, in that it's highly decentralized. They simply don't have the structure that would allow for a central authority to come in and confiscate property.
Because of this, they've long been considered a safe haven for metals like platinum, and the reason we recommend considering sending some there once you've accumulated a large amount.
When investing in any asset, including platinum, it's important to keep the time horizon in mind. Prices fluctuate, and over a longer time horizon there's a better chance of your investment appreciating in value.
The last thing anyone would want is to invest money they'll need in the coming months, only to have the market move against them. Talk to your financial adviser, and carefully plan any future purchases.
It's important to comply with the law when it comes to buying platinum, and knowing what they are goes a long way.
Under a certain dollar amount, there's no need to declare (which may be attractive to some), but once you hit a threshold you will need to (and should) declare your holdings.