Hey @cesarmd
Being new to PHP myself I found this question quite interesting and here is what I found:
The require() function is identical to include(), except that it handles errors differently. If an error occurs, the include() function generates a warning, but the script will continue execution. The require() generates a fatal error, and the script will stop.
Have a look here: https://stackoverflow.com/questions/2418473/difference-between-require-include-require-once-and-include-once