How to write an authorization letter that actually gets accepted
An authorization letter is a signed statement in which you (the principal) give a named person (the agent) permission to act on your behalf for a specific, limited purpose — collecting a parcel, accessing medical records, picking a child up from school, or handling one transaction at your bank. It is the everyday, low-formality cousin of a power of attorney, and for most routine errands it is exactly what the organisation in front of you expects.
Whether it is accepted has almost nothing to do with elegant wording and almost everything to do with whether the person at the counter can verify four things quickly: who you are, who you are naming, exactly what they may do, and until when.
What an authorization letter can and cannot do
It works well for a bounded, one-off or short-term task where the organisation simply needs written proof that the person in front of them is acting with your consent. It does not work where the law requires a formal instrument:
- Selling or mortgaging property, or signing a deed — you need a notarised power of attorney.
- Ongoing financial control (managing accounts indefinitely, filing tax returns on your behalf) — banks and tax authorities require their own forms. In the US the IRS uses Form 2848; in the UK you need a Lasting Power of Attorney registered with the Office of the Public Guardian.
- Decisions after you lose capacity — an ordinary authorization letter lapses precisely when it would matter most. Only a durable or lasting power of attorney survives incapacity.
If your situation is on that list, use a power of attorney instead — it is the same idea with the formality the law demands.
The six elements every recipient checks
- Your full identity as principal — legal name, address, and an ID or account number the recipient already holds for you. An account number is what turns a letter from a stranger into a letter from a customer.
- The agent, identified well enough to be matched to their ID — full legal name exactly as it appears on the document they will present, plus that document's number. "My brother David" is not identification.
- A scope narrow enough to be unambiguous — "to collect the parcel with tracking number RR123456789GB" beats "to handle my mail".
- Dates — a start date, and an end date wherever possible. Open-ended authorizations make compliance officers nervous, and nervous officers say no.
- Any limitation you want on the record — a ceiling amount, a single visit, view-only access.
- Your handwritten signature and the date of signing. A typed name is not a signature. Many institutions also want the agent to countersign.
Banking and financial authorizations
Banks are the strictest recipient you are likely to face, and most will not accept a free-form letter for anything beyond a single named transaction. Expect to be asked for the letter plus a copy of your ID, and expect the branch to phone you to confirm. Write the exact amount and the exact account numbers, cap the validity at a few days, and accept that a bank-specific mandate form may be required instead.
Medical records and care
In the United States, a general letter will not release medical records: HIPAA requires a written authorization naming the records, the recipient, the purpose and an expiration date, and most providers insist on their own form. In the UK and the EU, access requests under GDPR follow a similar logic — the provider needs to be satisfied the request genuinely comes from the patient. Write the letter, but call the practice first and ask whether they have a form; it will save you a wasted trip.
School pickup and childcare
Schools generally keep a standing list of authorized adults and will simply add your named person to it. Include the child's full name and class, the agent's name and ID, the exact dates, and state clearly whether the authorization is for a single day or a period. Most schools will still check ID at the gate — that is the system working as intended.
Parcels, mail and administrative errands
This is the most forgiving category and where a plain letter is most likely to be enough. Give the tracking or reference number, name the carrier or office, and have your agent bring both your letter and their own ID.
Vehicles
Letting someone drive your car generally needs no letter domestically, but a written authorization is routinely requested at borders and by rental and insurance companies when the driver is not the registered keeper. Include the registration number, the make and model, the exact dates, and confirm the driver is covered by your insurance — the letter does not extend cover on its own.
Do you need a witness or a notary?
For everyday errands, no. A dated handwritten signature is normally sufficient. Notarisation becomes worthwhile when the amounts are significant, when the document will be used abroad, or when the receiving organisation says so — and some countries will additionally require an apostille for a document issued elsewhere. When in doubt, ask the organisation what they accept before paying for anything.