Dear Ms. Hernandez,
Thank you for posting your request on History Hub!
To search for and get copies of Immigration records you would have to make a request for them at the Regional National Archives Facility associated with the port of entry. For example, the person flow into Los Angeles from Colombia their records would be located at the National Archives Facility in San Francisco. The list of National Archives Facilities are on this website: https://www.archives.gov/locations.
We hope this is helpful. Best of luck with your research!
Welcome to History Hub,
The following information is from a free site. familysearch.org. you just need to register to use. There is more information than what I gathered on the site for Pedro Pablo Isaza aka Peter Paul Isaza
List showing him as passenger
He was naturalized in 1939 and legally changed his name to Peter Paul Isaza.
Winnie, you need to click on document, there is a photo of him.
Is this the person who you are looking for? If not you need to give us his approximate birth year and where he lived in the US.