Shares are there for growth over many years. They give part-ownership of companies, and their prices can move a lot from one year to the next.
Bonds are loans that pay interest. They usually move less than shares and can soften a fall, though in some years both fall together.
Cash is for what you need soon: withdrawals, fees and anything planned in the next year or two. Holding it means nothing has to be sold in a hurry. General information, not advice.