Almost all of major exchanges block Iranian users. There are risks, but you can use fake identities, VPNs and such techniques to bypass restrictions. The main problem is converting among cryptocurrencies and USD, but there are channels and people that supply stable coins using links with neighbor countries. In fact, USDT price in Iran is just about 5% higher than USD. Having USDT or by mining, you can easily trade all cryptocurrencies, especially in crypto-to-crypto exchanges.
Also local exchanges like out startup operate in Iran to match domestic supply and demand without the need of external entities. But anyways, this is all about not-so-large sums of money and not government level transactions.
Also local exchanges like out startup operate in Iran to match domestic supply and demand without the need of external entities. But anyways, this is all about not-so-large sums of money and not government level transactions.