Yes, turning on the Multicurrency feature allows you to create transactions with foreign currencies. In addition, you can only create one currency per transaction at a time. If you want to create a transaction with another currency, you'll need to set up another customer or vendor profile with the correct currency.
As another option, explore this 3rd payment service to deal with multi currency transactions. You may release an invoice and get paid in SGD, and your client pays it in their local currency.