In one from my previous articles i described how to get old facebook pixel ID and how to insert facebook ads pixel to website with html box pro module usage. Unfortunately facebook no longer supports old pixels, so in this case we have to get new pixel ID. It's very easy process, you just have to copy it from your ads manager page. This tutorial is available as a part of facebook pixel prestashop module documentation 

If you've got pixel:

1. Go to your Facebook Pixel tab in Ads Manager and check screenshot attached below

If you don't have a pixel

1. Go to your Facebook Pixel tab in Ads Manager
2. Click Create a Pixel (if you dont have any)
3. Enter a name for your pixel. You can have only one pixel per ad account, so choose a name that represents your business (Note: You can change the name of the pixel later from the Facebook Pixel tab)
4. Check the box to accept the terms.
5. Click Create Pixel.
6. Now you will be able to get pixel ID, image below shows where it is