Google Webmaster Tools is a free service that helps you evaluate and maintain your website’s performance in search results

Google Webmaster Tools (GWT) is a conduit of information from the largest search engine in the world to you, offering insights into how it sees your website and helping you uncover issues that need fixing.

You do not need to use Google Webmaster Tools for your website to appear in search results, but it can offer you valuable information that can help with your marketing efforts.