We'll show you how Boost works in the Cash app. With Boost, you can quickly save money by using your credit card at cafes, restaurants and other businesses. How does boost work on cash app to get started, all you need is a bank card. If you already have a money card, follow these steps to start saving: Click the “Money card” tab on the home screen. Click "Save with acceleration". Tap Boost. Touch, add momentum. Start saving you can visit website for more details.