If you are using the desktop/browser version of our website, and you have an available (not allocated) balance on your balance page, you will see this BAKE button. 
With the button "BAKE", you can simply allocate your available balance into a Product (for example Lending, Staking, Liquidity Mining etc.).
For more information about our products, please check this article: Cake DeFi Services Simply Explained
For more information how to make a deposit, please check this article: How to make a deposit into my Cake DeFi account?