This article explains how to connect your Facebook ad account to Ad360 App for Shopify.
Ad360 will then be able to run and manage ads in your Facebook and Instagram accounts on your behalf.
Your Facebook ad account Id is a unique number provided by Facebook and used to identify your Facebook ad account.
You need an existing Facebook Ad account to perform this action. You can find your Facebook Ad account Id in your Facebook Ads manager account:
Your ad account ID number is shown above the search and filter bar, in the account dropdown menu.
1. Go to Ads Manager.
2. Your ad account ID number is shown above the search and filter bar, in the account dropdown menu.
Source: Facebook Business Help Center. If you weren't able to find your Facebook ad account ID, you can find more information in this Facebook Business Help Center article: https://www.facebook.com/business/help/1492627900875762