Focus keywords should be mentioned in the URL, page title, subtitles, and paragraphs with URL being the most important followed by page title then subtitles and finally paragraphs. Yoast is an on-page SEO tool and SEO WordPress plugin that helps with meta data like title, description and keywords as well as site maps, robots, and readability through using active voice, short sentences, subtitles, varied sentence structure, and transition words. Meta data contains information about the web page within the header tag including the title, description and keyword tags.