The safest first step is to ask what the identifier belongs to
Immigration notices can display several strings of letters and numbers on the same page. Entering the wrong one may produce an error, attach a case to the wrong workflow or expose private information to someone who never needed it.
Before copying an identifier, read the label beside it. An A-Number identifies a person when one has been assigned, a receipt number identifies one filing, a USCIS online account number is tied to an account, and an Online Access Code helps connect a paper-filed case to that account.
An A-Number is a person identifier
USCIS defines the Alien Registration Number, commonly called an A-Number, as a unique seven-, eight- or nine-digit number assigned by the Department of Homeland Security to a noncitizen. A person may see it printed as A followed by digits on an employment authorization document, Green Card, immigrant-data record or USCIS notice.
Not every applicant has an A-Number at every stage, and it is not a case-status tracking number. If a form asks for the A-Number, copy it from a reliable government document and follow the form's instructions for leading zeros rather than guessing from another reference number.
A receipt number identifies one USCIS filing
After accepting a filing, USCIS generally issues a receipt notice with a 13-character receipt number: three letters followed by 10 numbers. It is the identifier used in USCIS Case Status Online and in many communications about that particular application, petition or request.
One person can have several receipt numbers at the same time—for example, separate numbers for a petition, adjustment application and employment authorization request. A status message for one receipt does not automatically describe the others, so label each record with its form type and filing purpose.
The online account number belongs to the USCIS account
A USCIS online account number is associated with an individual's USCIS online account. It is different from both the A-Number and the receipt number, and it may appear on an account profile or an official notice.
USCIS says each person should have an individual account. Do not create multiple accounts to fix a missing case or let a relative, preparer or attorney use an account as though it belongs to the applicant; USCIS provides separate representative-account functions.
An Online Access Code links a paper case to an account
For many paper-filed cases with receipt numbers beginning IOE, USCIS sends an Online Access Code that can be used to add the case to an online account. Once linked, the account may show case history, notices, secure messages and document-upload options, depending on the form and case.
The access code is not the receipt number and should not be shared. If it has expired, was used in someone else's account or never arrived, USCIS provides an official request process for a new code and says processing can take up to seven days. USCIS also cautions that cases already placed in different accounts cannot simply be merged.
A simple filing-by-filing record prevents mix-ups
- Create one private row for each form with its form type, applicant or petitioner, filing date and receipt number.
- Record the A-Number separately as the person's identifier and copy it exactly from an official document.
- Keep the online account number and Online Access Code private; never place them in a public contact form or social-media message.
- Store the receipt notice and access-code notice as separate documents, even when they arrive together.
- If a case does not appear online, use USCIS technical support instead of opening repeated accounts.
Protect every identifier as personal information
A case number alone does not decide eligibility, but the combination of identifiers, name, date of birth and document images can enable fraud or unauthorized access. Share only what an official agency, licensed attorney or accredited representative actually needs, through a secure channel.
Information checked September 20, 2026. The location and format of identifiers can vary by document and benefit type, so use the label on the actual notice and current USCIS instructions when a form asks for a number.