Passport books have an information page, which contains the photo and personal information of the passport holders. US passports also contain multiple pages which are initially blank. These pages are used by border officials and custom officials in order to insert visas and other types of travel authorization when you travel. In most cases, a passport book comes with enough pages to support the average traveler. However, if you travel frequently, you may need to file USCIS Form DS-4085 (Application for Additional Visa Pages) in order to get new pages for your passport.
In most cases, customs officers and border officials can only place once stamp per page of your passport book. This means that if you travel often, you may eventually run out of passport books while your passport is still valid. Just because there are still blank spots on your passport pages, this does not mean that you can have new visas and stamps placed on your passport. You need to consider the total amount of blank pages left. If there are not many blank pages left, you do not need to
apply for a new passport. Instead, file Form DS4085 in order to get new pages for your passport.
When filing immigration form DS 4085, you will need to submit your current passport as well as an application fee along with the form itself. Since most of the time USCIS Form DS-4085 is filed by mail, you may wish to send Form DS4085 by courier or by a registered form of mail service which allows you to easily track your passport and your important documents. There is an option for expediting Form DS 4085 if you need your passport back quickly. It is a good idea in any event to submit Form DS-4085 as soon as you realize that you have just a few pages in your passport left or as soon as you realize that you will need additional pages. This helps ensure that you will have your passport and your new pages back by the time you need to travel.
If you need to travel suddenly and cannot apply for new passport pages in time but do not have enough passport pages, contact your nearest passport office. You can often arrange to come in in person to have pages added to your passport. You should not ignore the problem, however. If you do not have enough pages in your passport when you travel, you may not be able to get the required travel authorization and you may need to spend valuable travel time contacting US embassies or consulates at your destination for help.