If I turn it off how do I turn it back on

So, here's how to set up Apple Cash, although it sounds like you already know this part! :-). And here's how to manage Apple Cash, including how turn off Apple cash, as follows:

Turn off Apple Cash on a device

After you set up Apple Cash on one device, you can use it on any eligible device where you're signed in to iCloud with the same Apple ID. To turn off Apple Cash on a certain device, use these steps on the device: 

• • • iPhone or iPad: Open the Settings app, tap Wallet & Apple Pay, then turn off Apple Cash. 
    • Apple Watch: Open the Apple Watch app on your iPhone, tap Wallet & Apple Pay, then turn off Apple Cash.

To turn Apple Cash back on, you need to enter your Apple ID password.

The "how to manage" link provided earlier also contains instructions on "how to close your account," should you so choose.

Good luck!

JDee