You can file a Freedom of Information Act (FOIA) request with a federal agency in the United States by following these general steps:

1. Identify the agency that has the records you want to request. You can start by searching online for the agency's name and "FOIA" to find its FOIA office or contact information.

2. Write a letter or email to the agency's FOIA office that clearly describes the records you want to request. Be as specific as possible, including dates, names, and other relevant details to help the agency locate the records.

3. Provide your contact information, including your name, address, and phone number or email address.

4. Specify your preferred format for receiving the records, such as paper copies, electronic copies, or access to a reading room.

5. State your willingness to pay any fees associated with processing your request. The agency may charge fees for searching, reviewing, and copying the records, but you can request a fee waiver if you can show that you cannot afford to pay.

6. Sign and date your request.

7. Send your request by mail or email to the FOIA office of the agency that has the records you want to request. You can usually find the address or email address on the agency's website or by contacting the FOIA office directly.

It's important to note that each agency may have its own specific requirements or procedures for filing a FOIA request, so it's a good idea to check the agency's website or contact its FOIA office for detailed instructions before submitting your request.