The Polymath investment platform has been created to account for non-cryptocurrency assets on the blockchain. This means stocks, bonds, private equity and venture capital can now be tokenized on the ledger. This gives the traditional financial markets a way to use the exceptional security and accountability of the blockchain for their own companies.
They can do so by using what POLY calls STOs. Corporations will be given a simplified and legally secure way to launch their own regulatory friendly tokens on chain, a service that will likely be very desirable in the near future.
It's possible to buy Polymath on a few exchanges, but the options are rather limited, unfortunately. Ethereum and Bitcoin are the only viable trading pairs with enough liquidity to be worthwhile. Though there is a little volume for the Indian Rupee if that is your native government-issued currency.
POLY is an ERC20 token, and so you can store it in most any compatible Ethereum wallets. Make sure your wallet can store Ethereum tokens in addition to Ethereum itself. Some popular choices are My Ether Wallet or Meta Mask. In addition, several hardware wallets such as Ledger also support them.