what difference between current balance and uninvoiced balance in linode

The Current Balance is the amount your account owes based off of your usage up until that point in the month so far. The Uninvoiced Balance is an additional balance that will be due, but has been not been added to the current invoice balance yet. This can be further explained in the Viewing Current Balance section of our Billing Guide.

If i close my account and I have a 20$ coupon, and in my "Uninvoiced Balance" 10$ do I have to pay or the coupon is sufficient

The credits will cover the balance here. Balances are always applied to account credits before they generate charges to your payment card.

so do we have to pay the Uninvoiced Balance??
or only the due amount??

@Levi47 When closing your customer account, the total balance due- invoiced and uninvoiced- will need to be paid. I hope this clarifies things for you!

Let us know if you have any additional questions.