A:Answer WiFi means you can connect the iPad to any Wi-Fi access point like your home or a coffee shop. When you add “unlocked” to that, it means the iPad is also equipped with a cellular data modem that can be used on cellular data networks provided by cellular carriers (like a smart phone, but only data...no “voice” plan), but the iPad is not “locked” to a specific carrier when you buy it. You can choose a carrier and change carriers as you see fit. When a carrier is specified in the description, the iPad cellular modem is locked to that carrier and can only be moved to a different carrier after being unlocked by the original carrier. Usually this means the original carrier subsidized the price to some extent in order to get you to sign up for a wireless plan with a one or two year commitment. Unlocking the iPad would likely require that you pay the original carrier a fee for letting you out of the time commitment, if you terminate early. If you satisfy your service contract time commitment, you will still need to have the original carrier “unlock” the iPad from their network, if you want to change carriers at a future date.
Even with “WiFi only”, you can make voice and video “calls” over data using various “apps” (like FaceTime and Skype) as long as you are connected to a WiFi network. However, there is no phone app on the iPad, so you can’t make regular phone calls on the iPad even if you have the version that includes cellular data capability. Just like a laptop, it isn’t a “phone”.