A Keyword is a term that captures the essence of the topic of a document, article, blog post, or other piece of content. They are an integral part of how search engines retrieve web pages for search engine results pages.
Search engines are designed to search for words anywhere in a document—the title, the body, and so on. This being the case, a keyword can be any term that exists within the document. However, priority is given to words that occur in the title, words that recur numerous times, and words that are explicitly assigned as keywords within the coding (within the H1 tag, for example).
Keywords in ad campaigns
Ad campaigns are usually built to target a specific keyword, bidding on that keyword against other websites who want their content displayed when it’s searched for.
Keywords in meta tags
There was a time when the use of keywords in the “meta tag” section of a web page was important to search engine optimization. But Google ignores meta tag keywords now. You should use keywords in your meta tag description however, to influence the description shown on the SERPs.
Keywords in relation to content marketing
It’s good practice to build every piece of content around one keyword, or possibly as many as two or three. When crafting the content, make sure the keyword appears prominently. However, keyword placement should be natural, do not place it in the title or subheadings or in the content where it doesn’t make sense to a human being. You are creating content for people, bit algorithms.
Keywords for web pages
Every page of your website should be related to a keyword, and every keyword important for your website should have at least one page.