IRS Link to Form — Found Here
Sometimes individuals need representation to argue their case to the IRS or the tax court. To this end, there is an IRS form, the 2848, which designates an individual to represent the taxpayer on tax matters.
The person receiving agency must be qualified and certified to perform such work. CPAs, Enrolled Agents (EAs), tax attorneys, and a few other professionals are qualified to represent taxpayers (or non-taxpayers, as the case may be) on tax matters in a tax court or IRS audit. To give one of these registered tax advisors the authority to serve as your agent and proxy for such matters before the IRS and tax courts, you must file a Form 2848.
This will name the person you designate and give them permission to access your personal information and to act according to your best interest and in observance of the applicable laws governing taxes and taxpayers.