Hello, good afternoon, I would like to know what I need to bring to obtain an authorization, so that they can take my daughter out of El Salvador without me being there.

You can send a notarized letter from here

Good afternoon Mr. Cruz, for travel authorization the requirements are: Original birth certificate of the girl or boy who is going to travel, photocopy of a child's passport or girl who is going to travel, you must bring your current Salvadoran dui or passport, and if the child travels with someone, they must bring the photocopy of the identification document of that person traveling with the child.