When sending a domestic bank wire, you will need to provide the recipient's name, address, bank account number, and ABA number (routing number).
A bank account transfer letter is written to the branch manager of your bank to transfer your existing bank account from a certain branch of that bank to another branch in some other city.
To obtain a bank confirmation letter from your bank you may request in-person at a bank branch from one of the bankers, by a phone call to the bank, and depending on the financial institution, through their online platform.