User defined functions are where you create your own function to do someting. To make a function you first have to write function and then whatever you want to call it with parenthesis. I created the saini_family funtion that has the argument $name so whenever you call the saini_family function you have to pass the an argument in quotations. The saini_family function will that argument and echo out In the Saini family there is a ".$name. $name being whatever you assigned it