A tax ID verification letter is the official confirmation that the Internal Revenue Service sends following a request for an Employer Identification Number (EIN). The process to apply for an EIN ...

A benefits verification letter could be required for certain situations. "Because it is an official government document, it can be used as proof of income for financial and legal issues," Thelin says.

An income or benefit verification letter from Social Security is an official document issued by the Social Security Administration (SSA) that provides proof of your income or the benefits you ...

it will also include an official seal from the bank. Proof of funds and a preapproval letter serve distinctly different purposes. A preapproval letter and a POF letter are not the same.