An entity that wishes to transact in USD must load stablecoin on Stellar through AnchorUSD (anchorusd.com), a USD based stablecoin provider on the Stellar blockchain.
A stablecoin is an asset that is 1:1 with the Dollar or other assets, as specified by the issuing entity. A stablecoin can be used as a replacement for the Dollar, and can be transferred from one address to another similar to cryptocurrencies. On Stellar, AnchorUSD's stablecoin "USD" is 1:1 with the United States Dollar. AnchorUSD has a set of rules in place for entities who want to transact in its asset. These rules include KYC and AML verification, along with a registration on anchorusd.com.
Investors and receivers on Opensolar must purchase USD from AnchorUSD. A receiver must purchase USD to payback towards a project and an investor must purchase USD to invest in a project.
There are no known alternatives to AnchorUSD on the Stellar blockchain.
AnchorUSD is currently limited to the United States, and as a result, receivers and investors are restricted to the United States.