By default WordPress contact form 7 allows you to insert contact forms via shortcodes. You can use its shortcodes inside your blog posts, pages, text widgets and other shortcode supported areas. This tutorial is on new Contact Form 7 addon plugin called Widget Contact Form 7. This plugin after activation creates an easy to use contact form widget which you can quickly add to your sidebar and assign a contact form to show.
Installation & Usage: Install and activate Widget Contact Form 7. After activation visit your admin area Dashboard -> Appearance -> Widgets page and drag its widget to your sidebar. Finally select a contact form to display and click ‘Save’ button.