Governmental means “of a government” or “to do with government” — money, power, offices, rules that come from the state. It is a stiff adjective. We say governmental power, a governmental body, governmental control. Though actually, everyday English often just puts government in front of the noun instead: government policy, government money, government schools. That shorter form is what most people say. Governmental sounds more official, more like a report. The place learners keep meeting this word is in non-governmental: a non-governmental organization (an NGO) is a group that does public work but is not the state — a charity, a campaign group, a foundation. So the word is often useful in the negative: not the government.