Call the Collections Bureau at 617-887-6400 with any questions. How to Write an Authorization Letter Step 1: Write Your Name and Address.Step 2: Mention the Date. Check how to write an authorization letter to collect documents. Go through the format and samples to write a well-structured letter to Bank Authorisation Letter to Collect Documents: Writing an authorisation letter to the Bank Manager? Sample Authorization Letter for Opening Bank Account - Free download as (. It provides details of the author's personal bank account, including the bank name, account name, number, and type. Below you will find links to useful forms and documents for easy and convenient access. Bank letterhead; Account number; Routing number; Business name.