Is Verizon a cellular carrier

Verizon is not a partner with Apple for the Apple SIM, so you cannot select them as a carrier if you only have the Apple SIM in the iPad. They do support iPads and always have, but you need to go to Verizon and get a Verizon SIM to use with an iPad. AT&T, T-Mobile and Sprint are partners in the Apple SIM effort so you don't need to get a SIM from any of them - just use the included Apple SIM with those three.

That's because as Eric points out, Verizon is not a partner.

What that means, is you cannot set up the cellular service directly on the iPad through the Settings App, but rather you need to get a sim card from Verizon directly.

Partner carriers can be selected directly on the iPad and configured there, other carriers that support the iPad require the use of a physical sim card from them.

Verizon can be used on iPads, as mentioned, but you will need to call them up and get a sim card from them to insert into the iPad.

And iPads have been unlocked when bought directly from Apple since the 4th gen iPad I believe.

1st, 2ndand 3rd gen iPads had sepcific models for Verizon's CDMA network. But since even Verizon has switched to LTE for data, the CDMA only version is no longer required.

Verizon is a cellular carrier, where are you looking at this list that does not include Verizon?

Contact Verizon, the offer iPad cellular plans, but not sure what the details are.

Interesting. When I go through the Buy option on Apple.com, I can choose wi-fi+Cellular, and don't see the option to choose a carrier. I was just going to check to see why they were not on the list, but I don't even see a list. I've tried the website and the Apple Store app on my iPad and don't see a list of cellular providers. I'm sorry to send this into the wrong direction here for you, but you should not have an issue getting Verizon for a carrier.