A:Answer Verizon is also GSM. But GSM is only one part of the picture. You also need to see if the phone covers all frequencies necessary for your service. For Verizon the phone needs to cover 850 MHz, 1900 MHz, 700 MHz, 1700/2100 MHz.
So if Verizon is a CDMA only then please explain this:
https://www.bestbuy.com/site/motorola-moto-g6-with-32gb-memory-cell-phone-black-verizon/6251855.p?skuId=6251855&cmp=RMX&extStoreId=275&ref=212&loc=1&ds_rl=1255843&gclid=Cj0KCQjwn4ncBRCaARIsAFD5-gV6L86I6_881BZRKVi3rPxqAmDBZYaGOmYJIKVx3hyuwCqRgAbx3PgaAhrjEALw_wcB&gclsrc=aw.ds
Proof the above is a GSM SIM phone:
https://www.google.com/search?q=motorola+g6&oq=motorola+g6&aqs=chrome..69i57j69i60j69i61l2j0l2.6675j0j7&client=ms-android-verizon&sourceid=chrome-mobile&ie=UTF-8#lbl=DETAILS&pie=plaji-i
And for this post I am holding a Moto Droid Turbo 2. Of which is a GSM SIM on Verizon. Verizon what's to shutdown it's CDMA by 2019.
All carriers now have GSM capabilities. But does the phone you pick cover the frequencies or data protocol. It would be to easy for you to contact your carrier by dialing 611 from your cell and asking them it that phone model is compatible. Verizon has plans with no obligation if you bring your own phone.
Unless whoever is selling this phone put false frequencies and protocol in the description there is a good possibility it works on Verizon.