If you are unable to provide the required acceptable ID, such as a passport or REAL ID, you can pay a $45 fee to use TSA ConfirmID. TSA will then attempt to verify your identity so you can go through security; however, there is no guarantee TSA can do so.
Using TSA ConfirmID is optional. If you choose not to use it and don't have an acceptable ID, you may not be allowed through security and may miss your flight.
Continue to TSA's website to read more or to be directed to their payment portal.