You can add a Facebook Pixel to your website using Google Tag Manager
Step 1 - Link your Google Tag Manager account to your VIA software
Create a new GTM account at http://tagmanager.google.com , or use an existing account that you’ve already setup for your business
Login to your GTM account and copy your Google Tag Manager Container ID
Login to VIA
Go to Settings > Website > Onyx_Config
Paste your Google Tag Manager Container ID into the Google Tag Manager Code field
Click Save
Step 2 - Add your Facebook Pixel to Google Tag Manager
The guide below shows you how to add you Facebook Pixel to your website using Google Tag Manager