To create and use Facebook custom conversions, follow these steps:
Go to your Facebook Ads Manager and navigate to the "Events Manager" tab.
Click on "Custom Conversions" in the left-hand menu.
Click on the "Create Custom Conversion" button.
Choose the "Website" option for the source of your custom conversion.
Enter a name for your custom conversion and select the event you want to track.
Configure the details of your custom conversion, including the rule for tracking the event, the URL or category for the event, and the conversion value.
Click on the "Create" button to save your custom conversion.
Once you have created your custom conversion, you can use it to track and optimize your Facebook ads. Here's how:
Go to your Ads Manager and create a new ad or edit an existing ad.
In the "Ad Set" section, scroll down to the "Conversion" field and select "Custom Conversion" from the drop-down menu.
Select the custom conversion you want to use from the list of available conversions.
Save your ad and launch your campaign.
By using custom conversions, you can track specific actions on your website and optimize your ads for conversions based on those actions. Custom conversions can also help you track the performance of specific ad campaigns and ad sets.