The four classic categories are informational, commercial investigation, transactional and navigational, but the practical test is simpler: look at what already ranks. If the first page is full of comparison articles, Google has decided the query is a comparison query, and a product page will not win it regardless of how well optimised it is. The SERP is the answer key.
Intent mismatch is the most common cause of pages that are technically perfect and rank nowhere. It also explains cannibalisation: three pages written for what is really one intent split signals between them, and the fix is consolidation rather than more optimisation. Mapping every URL to exactly one intent is unglamorous work that routinely unlocks more traffic than a content sprint.