A Tag is a short snippet of code, usually from a third-party vendor, that companies implement on their site to collect data for analytics and digital marketing tools. 

A Tag Management Solution or System (TMS) is a platform that allows you to deploy all the tags on your website via a single container tag. Users can define rules/triggers within the TMS’s interface and then based on those rules, the container tag will fire other tags. 

The Conversions API is designed to create a direct and reliable connection between marketing data (such as website events and offline conversions) from your server, website platform or CRM to Meta. This marketing data helps power ad personalization, optimization and measurement on Meta so that your ads are shown to people who are more likely to be interested in them.