How to Sign as a Power of Attorney

By Cindy Cook DeRuyter - Updated March 15, 2018
Man signing power-of-attorney documents

When acting as someone else's agent under a valid power of attorney (POA) form, you have the legal authority to act in their place and to handle certain business, personal and financial transactions on their behalf. Knowing how to sign checks, documents and conduct transactions as an authorized agent, or power of attorney, can help you avoid personal legal responsibility.


Never sign someone else's name on checks or other financial transactions, as doing so could constitute fraud. Similarly, never sign your own name without also indicating that you are signing on someone else's behalf under authority of a power of attorney. document. Instead, follow the signing requirements of the state where the power of attorney form was created.

Understanding Your Role

Serving as someone else's agent under a power of attorney form helps ensure that the person can continue to meet financial obligations, even if she is not physically or mentally able to do so. Powers of attorney are authorized by state laws. The requirements to create a valid power of attorney, the powers granted and the legal requirements for acting in that role differ from state to state, so it is important to understand the specific laws that govern your actions. In all states, to act as someone else's agent, you must be at least 18 years old and mentally capable.

The Power of Attorney Form Can Limit Your Authority

Be sure you have legal authority to act before signing a document or executing a financial transaction for someone else. In some cases, your authority to act under a power of attorney on behalf of another person does not begin until that person becomes incapacitated or incompetent to act for themselves. In other cases, the power of attorney form takes effect immediately after the principal – the person creating the form – has signed it.

It is also important to clearly understand the scope of authority you have under the power of attorney form. When people create powers of attorney in an estate planning context, they generally give their named agent broad authority to handle all types of transactions. But powers of attorney can also be used to provide limited authority. For example, a power of attorney form may give the agent the ability to handle only real estate transactions on the principal's behalf, but not general banking transactions. Understand the limits of authority you have been granted and don't exceed your power.

Acceptable Signature Formats

It's always a good idea to first ask the specific financial institution or service provider if there is a specific format it requires for POA signatures, but there are several generally accepted methods of signing a form, document or check as an authorized agent under a power of attorney. If your name is Jane Doe, and the person who gave you power of attorney is John Doe, you could sign a document as:

  •  "Jane Doe, attorney-in-fact for John Doe" 
  • "John Doe, by Jane Doe, as attorney-in-fact for John Doe" 
  •  "John Doe, by Jane Doe under POA"

Finally, you should have the signed POA form with you when signing a document for someone else as their attorney-in-fact if the bank or other financial institution does not already have it on file. That legal document is proof that you are authorized to transact business on behalf of another person.

About the Author

Cindy Cook DeRuyter is an attorney in private practice and a freelance writer. She earned her J.D. from Mitchell Hamline School of Law in St. Paul, MN and her B.A. in Management and Communication from Concordia University in Mequon, WI. When she's not reading or writing, she enjoys spending time with her husband, their teenage son and their three dogs.

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