Google Tag Manager
Google tag manager is a useful tool that google has made to help the business owner with managing all of the different links to the different google services that they have for there website. What it does is replace all of the other links with just the one link that is added to your page to help keep it clean and organized.
arguable the most important thing that it does is it tracks conversions. Conversion tracking is very helpful for anyone trying to sell any product or service and keep track of the amount of money made on the services or products provided. With it being connected to google analytics it would also help you to understand where in the world or were your targeted audience is concentrated.