How banks prepare authorization letter certifying clients bank account?

Banks prepare an authorization letter certifying a client's bank account by first verifying the client's identity and account details. They then draft the letter, including relevant information such as the account holder's name, account number, and the purpose of the certification. After obtaining necessary approvals from bank officials, the letter is printed on official bank letterhead, signed, and sometimes stamped for authenticity. Finally, the client receives the letter either in person or through secure channels.