In fact, your problem is that there is no way to register both RMB and Hong Kong dollars on one voucher. In accounting practice, foreign exchange accounting vouchers are special, which is different from ordinary accounting vouchers, that is, there are special foreign currency accounting vouchers. If you use financial software to keep accounts, you can design it yourself. If it is handmade, you can go to the stationery store to buy a special foreign currency accounting voucher. Such a voucher can register both foreign currency and RMB, which can solve your problem.