Keyword research is the process of identifying the words and phrases people search for that are relevant to your business, then evaluating them by search volume, competition, and — most importantly — search intent: what the person actually wants when they type that query.
Search intent generally falls into a few categories: informational (learning something), commercial (comparing options), and transactional (ready to buy or contact someone). Targeting a transactional keyword with an informational blog post — or vice versa — is one of the most common reasons content ranks but doesn't convert.