The WordPress Sidebar and Footer Templates
The Sidebar and Footer templates are two of four main templates in WordPress. The difference between a template and a theme can cause confusion. Templates are individual files. Each template file provides the structure in which your content appears. A theme is a set of templates. The theme uses the templates to make the whole site.
The WordPress Sidebar template
The filename of the default Sidebar template is sidebar.php. Typically, the sidebar is displayed on the right or left side of your WordPress template. In the default Twenty Eleven theme, the sidebar is displayed on the right side of the template, by default.
Similarly to the Header template, the Sidebar template is called into the Main Index template with this function:
<?php get_sidebar(): ?>
This code calls the Sidebar template and all the information it contains into your blog page.
The Footer template in WordPress
The filename of the Footer template is footer.php. Usually, the footer sits at the bottom of the page and contains brief information about the site, such as copyright statements, credits to the theme designer or hosting company, or even a list of links to other pages within the site.
The default Twenty Eleven theme shows the site title and a statement that says Proudly powered by WordPress. You can use the footer to include all sorts of information about your site, however; you don’t have to restrict it to small bits of information.
Similarly to the Header and Sidebar templates, the Footer template is called into the Main Index template through this bit of code:
<?php get_footer(); ?>
This code calls the Footer and all the information it contains into your blog page.