Your proof that you paid your tax due will be your own bank or credit card statement and you can also check your online account with the IRS.
https://www.irs.gov/payments/your-online-account
Or...do you mean you are not sure of your e-file status?
https://turbotax.intuit.com/tax-tools/efile-status-lookup/
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**