The difference is, for example, that they don't charge interest. They can't indulge in some particularly risky or speculative transactions. There's actually a whole long list of requirements, such as not selling debt, that are derived from these basic prohibitions against interest taking and against excessive risk. So because of those specific rulings, they have to design the transactions in slightly different ways.
For example, rather than borrowing money to buy some goods, they'll have the bank buy the goods and then resell the goods to the customer, so the bank becomes involved as an owner at one stage of the transaction. That makes it lawful, from the Islamic perspective. Whereas if the bank lent the money to the customer, that's an interest-bearing loan, and that's not allowed. So they use slightly different routes, typically involving ownership of goods at some point, to achieve finance."
https://www.theguardian.com/commentisfree/michaeltomasky/201...