Before you delete your Cash App account you have to make sure that you have taken all your money out of your account because if the money is in your Cash App account and you get it deactivated. Then it will be difficult to get the money back. 

If you’ve already deleted your account, you just need to delete the app.  On Android, push down on the app to select it. Then, start to drag it toward the top of the screen. A trash bin icon will come up. Drag the app over the trash can and release it. You might have to confirm whether you actually want to delete the app. Push down on the app on an iPhone. If you have a newer version of an iPhone, you’ll need to tap “Rearrange Apps” when it pops up. After you’ve selected this, your apps will start shaking on the screen. As they shake, delete boxes will come up. Tap on the one associated with the Cash App, and that will remove the app.  Hope this helps.