The website used to pay a Texas State toll bill online depends on which entity sent the bill. For example, bills sent by MSB or the Central Texas Regional Mobility Authority are paid on PayTexasToll.com, by clicking the Bill Search Pay Online link under the Payment Options heading.
TxTag toll bills are paid online at TXTag.org, by clicking the Pay My Statement link on the left side of the home page, as of 2015. The statement or account number is required, as well as the ZIP code or license information. Bills received from the North Texas Tollway Authority are paid online at NTTA.org, by logging in via the Log In link or the Pay Zip Cash Bill link at the top of the home page.