Okay kiddo, let me put this in simpler terms for you. Colombianization of Leticia, Putumayo, and Caquetá refers to the process of the Colombian government taking control of these regions to establish their authority and sovereignty.
Before, there were some groups or factions that were running these areas and they were not under the control of the government. But the government wanted to make sure that all parts of Colombia should follow the same laws and regulations.
So they sent people and soldiers to these regions, set up offices and institutions, and took control of the area. This meant that they now had to follow Colombian laws and pay taxes to the government just like any other part of the country.
It was a way to make sure that everyone in Colombia was under the same rules and regulations and that there was no separation or difference in the law, regardless of where you lived. This process was called Colombianization, and it helped to make Colombia a more united country.