You can create your own Facebook app for your business, organization, or personal use by integrating it with your Facebook Page. The Facebook Developers platform has everything you need, including the necessary tools and guides to walk you through the process.
Facebook Business Page: The ULTIMATE Tutorial (Quick & Easy)
The following steps will guide you through the process of creating an app for Facebook Messenger. However, there are several other products you can choose for your app. The following steps also require that you have a Facebook page set up.
Navigate to developers.facebook.com in a web browser. If you are not already logged into your Facebook account, select Log In at the top right to log into your account.
Select My Apps at the top right, then select + Create App from the drop-down menu.