Have you tried your MyVerizon account online? It might have the information there.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
The SSID is the name of your wireless network. To find it simply power down the MiFi, note the difference in available networks, power up, note the difference and compare your results. You should be able to stumble upon your SSID with trial and error.
Are you sure you are not referring to the wireless password to connect to your MiFi?