You need to create a page template to do this. Be sure to check out the documentation on how to do this.
Basically, you need to make a copy of “page.php”, call it “page-wide.php”, and then open up that new file in your text editor.
You’ll want to add this to the top of page-wide.php, above all the rest of the code:
<?php
/*
Template Name: Wide Page
*/
?>
Next, you need to edit the div that controls the width of your main column. Find this line:
<div id="content-wrapper">
And replace it with this:
<div id="wide-content-wrapper">
Then, towards the bottom of the page, remove this line of code:
<?php get_sidebar(); ?>
Now you just need to add a little code to the bottom of your style.css file:
#wide-content-wrapper
{
width: 100%;
float: left;
}
Then you need to upload your new file, page-wide.php, and the file you changed, style.css, and then you are ready to start applying your template to your Pages.
To change the template that your pages use, simply edit the page, and in the attributes box in the right column you will see a dropdown menu for templates, choose “Wide Page”, and give it a try.
Good luck Jorge!