The data flow diagram for an online banking system shows how transactions and information move. It involves customers, bank staff, and administrators. Here the customers can transfer funds, check balances, and pay bills. The system can also handle transactions, create reports, and manage accounts. Bank staff and administrators oversee transaction processing and report generation. This DFD helps manage financial transactions securely and efficiently. It also gives customers real-time access to their accounts and financial details. It shows how strong security and smooth data flow build trust in online banking.