Final answer:
Only the taxpayer or a legally authorized individual such as a guardian, executor, or trustee can represent someone before the IRS without a power of attorney. For other representations, a power of attorney form must be completed and submitted to the IRS.
Step-by-step explanation:
Individuals who wish to represent themselves or others in front of the Internal Revenue Service (IRS) without a power of attorney must be the taxpayer themselves or an individual legally authorized to act on the taxpayer’s behalf in a legal capacity such as a guardian, executor, or trustee of the taxpayer’s estate. If someone other than the taxpayer is to interact with the IRS, a power of attorney form, specifically IRS Form 2848, must be completed and submitted to authorize this representation. There are also certain professionals, such as attorneys, certified public accountants (CPAs), or enrolled agents who have the credentials to represent taxpayers before the IRS; however, they would typically also require a power of attorney unless they are representing the taxpayer concerning documentation, such as a tax return, they prepared.