If you apply for asylum, there are two different applications to choose between. Which application you choose will depend on whether any formal removal proceedings began. Before you apply for asylum, it is crucial to know the differences between the options so that you choose correctly. 

The United States Citizenship and Immigration Services explains the differences between defensive and affirmative asylum processing. 

Defensive asylum 

To use the defensive asylum application, you must be in the middle of removal proceedings in immigration court. There are two ways that you may find yourself in defensive asylum processing. The first way is for a judge to find you ineligible for asylum during affirmative asylum processing. The second way is if the U.S. apprehended you at the port of entry or if you did not have the proper documentation at customs. During the process, the judge will hear arguments in a courtroom like proceeding. 

Affirmative asylum 

To apply for affirmative asylum, it does not matter how you arrived in the United States. You simply must apply for asylum within a year of your arrival. Now, there are exceptions to the one-year rule if you had special circumstances that would require you to wait longer. You would fill out the application and while you wait for word on your eligibility, you can typically live in the United States. Once you file, you would meet with an officer that determines whether your case is eligible or not. If you are not eligible, then you may have to meet with an immigration judge or go through the defensive asylum process.