How To Sign as a Document as Power of Attorney (POA)

A Power of Attorney (POA) is a legal document that authorizes someone you trust—known as an agent—to act on your behalf. This can include signing documents, managing finances, or making health care decisions, depending on the type of authority granted. It’s important to know that a POA does not replace a signature—it simply grants permission for your agent to sign in your place. To make that authority clear, the agent must follow the proper format when signing.

Here’s what you need to know about how to sign as Power of Attorney—and how to use a POA appropriately.

How to sign as Power of Attorney

When you're signing on behalf of someone else under a Power of Attorney, you’ll need to include both your name and the principal’s name (the person who granted you authority), along with a clear indication that you are acting as their agent.

A typical signature format looks like this:
[Principal’s Full Legal Name] by [Your Full Name], as Power of Attorney

This format makes it clear that you’re not signing for yourself—you’re signing on behalf of someone else, with legal permission to do so.

What is Power of Attorney?

A Power of Attorney is a legal document that allows someone to act in your place. Depending on how the document is written, the agent may be authorized to handle finances, make medical decisions, or complete specific tasks on your behalf. The person acting under a POA has a fiduciary responsibility to act in your best interest.

Because there are several types of POA, it’s important to understand which one fits your needs:

• General Power of Attorney – Grants broad authority to act on your behalf.

• Limited Power of Attorney – Restricts the agent’s authority to specific actions or a set timeframe.

• Durable Power of Attorney – Remains in effect even if you become incapacitated.

• Healthcare Power of Attorney – Allows the agent to make medical decisions on your behalf.

• Financial Power of Attorney – Allows the agent to manage your financial affairs.

Although “Power of Attorney” includes the word “attorney,” it doesn’t require a lawyer to be involved. That said, it's wise to seek expert guidance to ensure you’re granting the right level of authority in the right way.

Keep in mind: A Power of Attorney only applies while you're alive. Once a person passes away, the POA is no longer valid. At that point, a Will or Trust becomes the guiding document for managing the estate.

Can a Power of Attorney be transferred to someone else?

No—an agent under a Power of Attorney cannot transfer their authority to another person. If the principal wants to appoint a new agent, they must revoke the current POA and create a new one naming the new agent. This ensures that the principal remains in full control of who is authorized to act on their behalf.

How do you sign for someone when you have Power of Attorney?

The most common and accepted format is:

[Principal’s Full Legal Name] by [Your Name], as Power of Attorney

For example, if the principal is John Henry and you are Larry Frank, you would sign as:
John Henry by Larry Frank, as Power of Attorney

Always check with the recipient (such as a bank or institution) to confirm their preferred format. Most importantly, never sign a document without clearly indicating your role as Power of Attorney.

How do I sign a check as Power of Attorney?

When signing a check, space can be limited. In that case, you can abbreviate "Power of Attorney" to "POA." A proper format might look like this:

John Henry by Larry Frank, POA

Just as with other documents, the goal is to make it clear that you are signing on behalf of the principal. Always have a copy of the POA document available in case you're asked to provide proof of your authority.

What are some examples of how to sign as a Power of Attorney agent?

Here are a few formatting examples to follow:

• Elizabeth James by Sarah Collins, as Power of Attorney

• Thomas Nguyen by Daniel Wu, POA

• Michael Taylor by Jordan Smith, Attorney-in-Fact under POA

Consistency and clarity are key—your signature should clearly reflect your role as the authorized agent.

What are common mistakes to avoid when signing as POA?

Acting as a Power of Attorney comes with responsibilities—and signing incorrectly can create confusion or delays. Avoid these common errors:

• Signing outside the scope of your authority

• Leaving out the principal’s name

• Forgetting to include “Power of Attorney” or “POA”

• Signing only your name (or only the principal’s)

• Failing to bring your POA document when signing important forms

Take your role seriously. When in doubt, ask the requesting party for guidance.

What can a Power of Attorney not do?

Even the most comprehensive Power of Attorney has limits. Here’s what an agent under a POA typically cannot do:

• Make decisions after the principal’s death

• Vote or make personal decisions like marriage on the principal’s behalf

• Modify or create the principal’s estate plan (e.g., write or change a Will)

• Transfer their authority to another person

• Distribute inheritance or handle estate matters after death (those are handled through a Will or Trust)

• Make medical decisions—unless specifically authorized by a Healthcare Power of Attorney

Understanding these limits helps protect both the principal and the agent from unintended consequences.

When does Power of Attorney end?

A Power of Attorney can end in several ways:

• If the document specifies an expiration date

• If the principal revokes the POA

• If the principal becomes incapacitated and the POA is not durable

• When the principal passes away

While a Power of Attorney ends upon death, it’s still a vital part of an estate plan—particularly for planning during your lifetime.

To ensure your estate planning covers all necessary details, take advantage of affordable and accessible estate planning services online at Trust & Will.  

At Trust & Will, we keep things simple. You can create a fully customizable, state-specific estate plan from the comfort of your own home. Take our free quiz to see where you should get started, or compare our different estate planning and settlement  options today!

Is there a question here we didn’t answer? Browse more topics in our learn center, visit our Frequently Asked Questions (FAQ) page,  or chat with our member support!

Trust & Will is an online service providing legal forms and information. We are not a law firm and we do not provide legal advice.