Hello, how do I know if I have successfully payed the irs?

[DoninGA]

You would have a cancelled check, bank or credit card statement showing the payment to the IRS depending on how you chose to pay the taxes owed.

You can also check your tax account for payments made - https://www.irs.gov/payments/view-your-tax-account

[DanPaul02]

Here is an article with five ways to check your IRS balance.