Role of a script writer

Okay, so, to be honest,I didn't really know what a script writer was until I got researching, its basically someone who writes a screenplay in which you need good story writing skills and a good imagination (which actually appeals to me since i have a good imagination).Every script starts with a theme or idea with the script writer intending on selling them and having them produced, Screenwriters are not hired, as they are 'contracted freelancers'. A lot of screenwriters start their careers writing on speculation also known as a 'spec' this means they write without being hired or paid,if a producer likes the script,and the script writer decided to sell their script, this is called a spec script. 
The basics in which should go into a script is concepts, characters, plot and the structure.By concepts it means what the films about and what you intend the actors to say, without a scrip writer they'd be no script and so no order on set. The characters within a script are essential as you need to know who the film is about and the main characters, You also need to include the protagonists and antagonists of the movie, the script writer needs to have a good ability to develop a character and make them believable.The plot is what drives the story and what happens to the characters to make the story line, the plot needs to be engaging otherwise it'll bore the audience making it unsuccessful.

Script writers use this particular font ( 12-point courier) as the standard screenplay format is designed so that one page approximately equals one minute of screen time, consistent character spacing is important.