I finished my taxes. I owe federal taxes. I put in my account number. I am looking for documentation that I paid. Where do I find that.

It is not paid until it is processed by the IRS or state.  You should create an online account at the IRS to monitor activity on your account.

TurboTax will never show that you paid the IRS.   Your TT account will always show that you had an amount due.  Your proof that you paid will be your own bank or credit card statement and you can look at the payments you made in your online IRS account.

https://www.irs.gov/payments/your-online-account