Why I can’t update coin master

Based on this, you can update from the App Store.

See -> If you can't make purchases or update apps, including free apps, you need to update your payment method or add a new one. 

See the following Apple articles:

Payment methods you can use with your Apple ID

Payment methods you can use with your Apple ID – Apple Support (UK) 

Add money to your Apple ID balance

Add money to your Apple Account balance – Apple Support (UK)

What happens when you try? Error message(s)?