In Spanish, when a police officer traps a criminal it's called "reduce", i.e. "El policía redució al criminal". The literal translation of "reduce" to English is also reduce, but I believe this is one of the meaning the English word doesn't have (correct me if I'm wrong). Therefore, how should I call the act of a criminal being handcuffed or trapped by the police?
The criminal was arrested by the police.
Arrest does have a legal sense, when the police take somebody's freedom. They would normally handcuff someone when they are arrested.
"Subdue" means "bring under control". Police officers learn to subdue a knife-wielding criminal without lethal force.
"overcome" It took three officers to overcome the violent criminal.
"restrain". The criminal was restrained by one officer while a second called for backup.
The only example I could find online of the use of "reduce" was "la policía redució al atacante a tiros." which seems to indicate that "Police shot the attacker".
The question was about putting handcuffs on a person. For that the word must surely be "restrain".
Arrest has a technical meaning in English law, and although @James K is right in saying that the police might well handcuff a person who has been arrested, that is incidental to the legal effect of arrest. It is certain that an arrest can occur without handcuffs being involved in any way. For example a prisoner already in jail for one crime might be arrested for another alleged offence.
The word is detained. You can be cuffed while being detained for questioning and to ensure safety while figuring out a situation.
You can be detained and handcuffed without being legally arrested. The officer has to tell the suspect that they haven't yet been arrested or charged with a crime, that the officer is handcuffing to ensure safety, and that they may be released after the questioning.