The meta keywords tag is a piece of code put in the <head> of a website that was previously used to help search engines determine for which terms the website should rank. It is no longer used as a ranking factor, though the search engines have said that they do not penalized websites that use it heavily.
Here is an example:
<meta name=”keywords” content=”SEO consultants, SEO agencies, digital marketing agencies, clowns”>
The meta keywords tag is not used for SEO and anyone telling you otherwise is incorrect. The meta keywords tag has not been used as a ranking factor since at least 2009, and many sites do not even include it within the <head> of their pages anymore.