An address line is a single row in a form or mailing label where you type part of your street address

An address line is a text field on a form, website, or document where you enter one piece of your mailing address. Most forms split your full address across two or three separate lines instead of asking for everything at once. The first line usually holds your street number and street name. The second line (often labeled "Address Line 2") holds an apartment number, suite number, or other unit identifier if you have one. Some forms add a third line for additional details.

The reason forms use multiple lines is practical: it makes addresses easier to read, sort, and process — especially when a computer system needs to verify the address or a mail carrier needs to scan it. A single long field would be harder for both humans and software to parse correctly.

Key Takeaways

  • Address Line 1 is where you enter your street number and street name, such as "742 Evergreen Terrace".
  • Address Line 2 is for apartment, suite, unit, or building numbers — leave it blank if you do not have one.
  • Some forms ask for city, state, and ZIP code on separate lines; others combine them into one field.
  • Postal abbreviations for states (like CA, NY, TX) are standard on forms, though some systems accept full state names.

What goes on Address Line 1

Address Line 1 is where you type your street address: the house or building number, the street name, and the street type (Street, Avenue, Road, Drive, and so on). Write it exactly as it appears on your mail or property documents. Examples include "123 Main Street", "4567 Oak Avenue", or "890 Maple Road".

Do not include your apartment or unit number on Line 1. Do not include your city, state, or ZIP code. Line 1 is for the street address only. If you are unsure of the exact format, check a recent piece of mail sent to that address — the postal service has already formatted it correctly for you.

What goes on Address Line 2

Address Line 2 is optional and is meant for secondary address information. This includes apartment numbers (Apt 5B), suite numbers (Suite 200), unit numbers (Unit 12), or building names if your address has one. Write it as "Apt 5B", "Suite 200", or "Unit 12" — do not repeat the street address.

If you live in a house or building with no apartment or unit number, leave Address Line 2 blank. Leaving it empty does not cause a problem; many addresses do not need it. Some forms do not include an Address Line 2 field at all, which is fine — the form is designed for simpler addresses.

City, state, and ZIP code fields

After the address lines, forms ask for your city, state, and ZIP code. These may appear on separate fields or combined into one, depending on the form. Type your city name in full (not abbreviated), select or type your state using the two-letter postal abbreviation (CA for California, NY for New York, TX for Texas), and enter your five-digit ZIP code.

Some online forms have a lookup feature: you type your ZIP code and the city and state fill in automatically. Others let you type the city name and suggest matching ZIP codes. If the form does not have this feature, you can find your ZIP code on USPS.com by entering your street address.

Common mistakes when filling address lines

The most common error is putting the apartment or unit number on Address Line 1 instead of Line 2. This can cause mail delivery problems or form processing errors because the system expects the street address only on the first line. Always move unit information to Line 2 if the form provides it.

Another frequent mistake is abbreviating the city name (writing "SF" instead of "San Francisco" or "LA" instead of "Los Angeles"). Forms expect the full city name. Abbreviating the street type (writing "St" instead of "Street") is usually acceptable, but writing it out in full is safer and more standard.

Typing extra spaces, punctuation, or information that does not belong (like a phone number or building name in the street address field) can also cause the form to reject the entry or route mail incorrectly. Stick to what each field asks for.

Address lines on shipping and billing forms

When you order something online, you typically fill out both a shipping address and a billing address. The address line format is the same for both: Line 1 for the street address, Line 2 for the unit or apartment number. Some websites let you copy the billing address to the shipping address with one click if they are the same.

If your billing address and shipping address are different — for example, you are sending a gift to someone else — make sure you fill out both forms completely and correctly. Double-check the shipping address in particular, since that is where the package will go. A mistake there means the item arrives at the wrong place.

International addresses and address lines

If you are entering an address outside the United States, the format may be different. Some countries use postal codes instead of ZIP codes, or arrange address information in a different order. Many online forms have a country dropdown that changes the address fields to match that country's standard format.

If you are filling out a U.S. form with an international address, look for an "International Address" option or a country selector. If the form only accepts U.S. addresses and you need to enter a foreign address, contact the organization running the form — they may have a separate process for international customers.

Frequently Asked Questions

Do I need to capitalize the street name and city?

Yes. Standard address format capitalizes the first letter of each word in the street name and city. Write "123 Main Street" and "San Francisco", not "123 main street" and "san francisco". Most postal systems and form processors expect this format and may reject or misread lowercase entries.

What if my address does not have a street number?

Some rural or rural-adjacent addresses do not have a traditional street number. In that case, write what you do have on Address Line 1 — for example, "Old Mill Road" or "County Road 42". If the form requires a number, contact the organization to ask how to handle your address type.

Can I use a PO Box as my address?

Yes, but format it correctly. On Address Line 1, write "PO Box" followed by the box number, such as "PO Box 567". Do not put it on Line 2. The city, state, and ZIP code go in their normal fields. Some forms reject PO Boxes for shipping addresses because packages cannot be delivered to them, but they are fine for billing or mailing addresses.

What if my street name has a direction in it, like "North" or "East"?

Include the direction as part of the street name. Write "123 North Main Street" or "456 East Oak Avenue" on Address Line 1. The direction is part of the official address and helps mail carriers and delivery services find the correct location.

Should I include my name on an address line?

No. Address lines are for the street address only. Your name goes in a separate field labeled "Name", "Full Name", or "Recipient Name". Putting your name in an address line confuses mail sorting systems and form processors.