In short: investing means putting money today into something that may produce income or rise in value in the future — with no guarantee, because its value can also fall.
Simply put: Saving keeps money safe for near goals. Investing is for money you will not need for a long time: you buy a piece of a company, lend to a government or a company, or join a fund. There is a chance of more, but no certainty. So the order is: emergency fund first, then the goal, the time frame and only then a product.
Example: Eva has an emergency fund covering six months of expenses. Separately, she sets aside €2,000 she will not need for at least ten years. Only those €2,000 are money she might consider investing; the emergency fund stays in an account.
Watch out: money you will need in a few months is not money for investing — the time frame is too short to wait for a recovery after a fall. And the framework's rule: do not invest in what you do not understand.
Source: EU/OECD-INFE, Financial competence framework for adults in the European Union (2022), topic 2.4 — https://finance.ec.europa.eu/publications/commission-and-oecd-infe-publish-joint-framework-adults-improve-individuals-financial-skills_en