Google analytics is a free tool that can help a lot improving you SEO
Search Console Tool is too a great tool to see traffic to improve your website and to index your pages on google
Ubersuggest is another free tool that can give great info's about you website your competitors and the keywords you want to rank on google.
There is too, a great free tool called SEO ONLINE TOOL hat can help you a lot to improve your website on google ranking. It offers an easy-to-understand and comprehensive set of SEO tools to help you understand your website from a search engine's perspective. In just a matter of few seconds and a couple of clicks, you can see how a search engine may interpret your site. Our SEO reports also let you know of any problems or technical shortcomings in your website that may be hurting your search engine rankings.
All the best!