Both a Power of Attorney and a Declaration are used on this form (Form POA), but they serve different purposes. A Power of Attorney grants someone (the Attorney-in-Fact or Agent) the authority to act on your behalf before the Internal Revenue Service (IRS) regarding tax matters. A Declaration, on the other hand, is a statement made by you, the taxpayer, regarding certain facts, such as your identity, tax matters, and appointment of an Agent. The Power of Attorney grants the Agent the legal authority to act on your behalf, while the Declaration provides the IRS with important information about you and your Agent.