Every page needs to have unique keywords that match the content in it. An expert SEO pro will be able to derive all possible highly generic keyword combinations that a user would try out on a search engine. Generic keywords need to be used in order for you to enjoy targeted traffic that can convert into revenue, rather than ending up with un-convertible page visits.
Based on your research, keywords entered into each webpage needs to be revisited periodically and tweaked if required.
Keyword Suggestion Tools can tell you the search phrases people use to find products and services, as well as the search terms that drive traffic to your competitors.
Keyword research is the foundation for all natural search engine optimization techniques since such keywords are based on actual search volumes and derived from user behavior on the internet.