You should always use the best tools and software for your On-site SEO. For example, if you are using the WordPress content management system for your website then there is plenty for free tools and plugins available for you. WordPress is very popular CMS so there are not 1,2 but hundreds of plugins available which can help you in this task. some of them are :

– Yoast SEO
– All in One SEO
– Keyword Tool
– Broken Link Checker
– EWWW Image Optimizer