Pages can be added to a passport.
You are planning to travel soon, but a cursory look at your passport reveals that it is almost full. That last thing you want is to run out of space in your passport when travelling overseas. Obtaining additional pages for a passport is simple and typically free.
How Many Pages?
The first question you must ask yourself is: how many pages does my passport have left? If you have more than four blank, unused pages in your passport, the National Passport Processing Center will refuse to add more. If, however, you have four pages or less of blank space, you are eligible to add more pages.
Now that you've ascertained that your passport is eligible for additional pages to be added, you must fill out Form DS-4085: Application for Additional Visa Pages. This form can either be printed out and filled out by hand or filled out online at the U.S. Department of State website. The form itself is only one page and requires basic personal information, including an emergency contact.
Mail It In
After filling out Form DS-4085, you are ready to send both it and your passport to the National Passport Processing Center in Philadelphia. If you filled out the form online, you need only mail in your passport. Send the materials to the National Passport Processing Center, Post Office Box 90106, Philadelphia, PA 19190-0106. Be sure to mail this in at least a month before you plan on leaving for your trip; this service is free, but can take between two and three weeks to complete.