To prospective or upgrading hams, there is a specific process and several requirements that must be met when attending a VE test session. You have studied hard and prepared for the test, if you do your preparation ahead of the VE session it will go smooth with no frustration and allow you to relax during the test.
For a new candidate testing for you initial (first) license you will need two forms of Identification along with a Federal Registration Number (FRN) obtained from the Universal Licensing System (ULS).
Licensed Amateurs looking to upgrade also need two forms of Identification, a FRN and your CSCE from your past exam sessions.
If yo plan on attending a GOTAhams VE exam it is preferred that you pre-register online at HamStudy.org, you will still need your other paperwork but simply to verify its accuracy.