What is Google Search Console?
It is a web service, provided free of charge for webmasters, which allows them to check indexing status and optimize visibility of their websites. Its tools and reports help you measure your site's Search traffic and performance, fix issues, and make your site shine in search results.
What is Google Tag Manager?
Tag Manager gives you the ability to add and update your own tags for conversion tracking, site analytics, remarketing, and more. There are nearly endless ways to track user behavior across your sites and apps, and the intuitive design lets you change tags whenever you want.