If you can get to the United States, whether by coming to the border or by traveling on a nonimmigrant visa or under the Visa Waiver Program, you can in theory apply for asylum upon your arrival. You would tell the Customs and Border Protection (CBP) inspections officer that you fear returning to your country and wish to apply for asylum. However, various barriers have been erected in recent years, as described below, and the matter isn't fully settled yet. Basically, now might not be the best time to try this strategy.
Some years ago, the Trump Administration instituted so-called "Migrant Protection Protocols" or MPP, more commonly known as the "Remain in Mexico" program. It stopped allowing asylum seekers into the U.S. to have their claims for heard. Instead, they were sent to Mexico to await the outcome of their cases. This meant waiting in difficult and often dangerous conditions or crowded camps, where it was hard to even stay in communication regarding upcoming hearings or other processing. It took litigation all the way to the Supreme Court before this policy was ended, in June 2022.
In 2023 however, regulations passed by the Biden Administration attempted to achieve much the same effect. These, too, were put on hold by a federal court. The court took particular issue with the new rule's presumption that people entering the United States through its southwest land or coastal borders are not eligible for asylum, unless they can demonstrate an exception or rebut the presumption.
Something called "Title 42" was also used to bar asylum seekers on public health grounds during the COVID-19 pandemic, but this was ended in 2023.
Even without hurdles such as the MPP, there are many reasons to avoid requesting asylum at the port of entry to the United States at this time.
One longstanding issue is that the CBP inspections officer with whom border entrants normally have their first encounter have the power to quickly find migrants inadmissible and deport them. The deportee will not be allowed to return to the United States for five years. This can happen if an inspector believes that the person is making a misrepresentation (committing fraud), misrepresented the truth when getting a U.S. visa, or does not have proper U.S. entry documents. This quick deportation procedure is known as "summary exclusion." It can be applied to anyone except people entering the United States under the Visa Waiver Program (according to a 1999 decision by the Board of Immigration Appeals).
In theory, there is an exception to the summary exclusion process for people who fear persecution and request asylum. So even if you do not have the proper documents or you have made a misrepresentation, you could, in theory, be allowed to apply for asylum if you can show that you'd be likely to win.
But getting someone to listen is currently a challenge. The Biden Administration instituted procedures whereby applicants are expected to use a phone app called CBPOne to make appointments to be screened as prospective asylum applicants ("credible fear interviews") by an asylum officer, but not all migrants have phones, and those who do have had difficulty getting through. Reports are that CBP officials will also arrange meetings for other migrants once the scheduled appointments are done for the day.
The "credible fear" interview is administered by an actual asylum officer, who is trained to hear such cases, and whose primary role is not enforcement. The interview's purpose is to see whether you have a significant possibility of winning your case, and should therefore be allowed to continue. Most importantly, the officer will want to be sure that your request is based on an actual fear of persecution. But it's rare to be allowed to have an attorney help you, and these interviews are commonly conducted by phone, and quickly, making it an impersonal process at which it's difficult to tell your full story.
Where will you be while you await your credible fear interview? That, too, seems to be in flux. It could be in Mexico or in a CBP detention center near the border.
If the asylum officer isn't convinced of your fear, you will need to request a hearing before an immigration judge in order to move forward. If you don't, you will (as mentioned above) be deported from the U.S. and not be allowed to return for five years. The immigration judge is supposed to hold the hearing within seven days, either in person or by telephone.
If the asylum officer or immigration judge also finds that you have a credible fear of persecution, you'll be scheduled for a full hearing. In that case, you should definitely seek an attorney to help you prepare your application and testimony. It's possible you will be kept in detention during this time as well; or you could be "paroled" into the United States and allowed to stay at least until your case is heard.
If you have some other way to enter the United States, such as on a B-2 tourist visa, you can apply for asylum by mailing in an application, with supporting documentation, on Form I-589. The form and instructions are available for free download on the USCIS website. However, if at all possible, you should get help from an attorney.