Any Verizon router device has a Reset button on the back, usually with a red circle icon. If you use the tip of a ballpoint pen or something (like a toothpick), press and hold the button until the signal light on the router turns off, then turn it on again. This process usually takes about 10 - 30 seconds:
And after resetting the router, the next thing is to use the device's default account, including username and password. Normally the username will be admin, and the password will be one of the following options: password, admin, serial number (each router device has a serial number on the genuine stamp) or a blank password.
If it fails, try resetting and keep trying again. And below is a detailed table of some popular, widely used router models:
And after you have successfully logged in, you need to change this default password. Choose Quick Links > Change Login User Name / Password as shown below: