Below we will see how you can add Facebook Messenger to your website without a plugin. In SecNews we added the widget inside the publications because we are somewhat sick with the speed of the Home. Of course you can place the widget where you want.
Below you will find the widget code. With a copy paste, your website will get it Facebook Messenger chat box and will enable your visitors to contact you directly.
At three different points of the code you should add your own Facebook page, or your personal profile page, depending on who you want the recipient of the messages sent by your visitors.
In the above code there are 3 addresses leading to our Facebook page (https://www.facebook.com/SecNews/).
Do not forget to put on your three pages your own page. Then save the widget and you'll see the icon that allows you to send messages from your page to where you chose.
The idea is from the DI, and the customization of our own code.