Start by visiting the Developer App. If you haven’t created an application before you will be prompted to add the Developer Application.
After that you’ll be able to create a new app.
Please note you must have verified your Facebook account to create apps on Facebook. Visit here for more information on verifying your account.
Create and Name Your New App
Click “+ Create New App” from the top right-hand corner. You’ll need to provide a “App Name“, which is what your “app”, or Facebook page tab, will be called. You’ll also need to create a “namespace,” which is basically just a unique ID for your app.
Configuring your App
Apps on Facebook are loaded into the Canvas section of the Canvas Page. For example, suppose that you have a WordPress post, page or custom post type available at
http://www.your-site.com/your-post. This is your Canvas URL.
Once you’ve created a Facebook app, select the “App on Facebook” section and specify a Canvas URL and Secure Canvas URL:
Configuring a Page Tab
In order to enable this feature, you need to specify a Page Tab Name and a Page Tab URL (much like you provided a Canvas Page and Canvas URL previously) that is loaded when the user selects your Tab on a given Facebook Page. You must also specify a Secure Page Tab URL which is the HTTPS address of your content. Users browsing Facebook who have HTTPS enabled will be unable to use your tab if this URL is empty. Note that SSL support for your page tab app has been mandatory since October 1, 2011.
You can find these settings in the “Basic” section of your app’s settings in the Developer App under ‘Select how your app integrates with Facebook’. Click ‘Page Tab’ to expand the Page Tab settings, and the Page Tab fields will appear
Page Tab Width
The amount of space available to your tab app is bounded by the outer context of Facebook. It may be configured to display with a width of 520 pixels (default) or 810 pixels.