Foreign Exchange Receivables are earnings of entities denominated in foreign currencies. Usually, these are earned by exporting services or goods.
For example, XYZ Pvt. Ltd. sold goods worth ₹ 10,00,000 to ABC Ltd. of USA with settlement being made after 3 months. If the money is received by XYZ in Rupee itself, it will not have any foreign exchange receivables although export is made. However, most of the international transactions are done in USD or convertible foreign currencies. Here if say, amount is payable in USD by ABC Ltd., XYZ Pvt. Ltd. will have foreign exchange receivable after three months amounting to USD 15,385 (Amount being fixed on day of sale @ 1 USD/INR = 65 ).