A:AnswerIt 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.
A:AnswerIf the iPad is WiFi + Cellular it uses a Nano-SIM card slot. It also supports eSIM. The iPad 8th gen also has an embedded Apple SIM that is built into the iPad. Check with your carrier for compatibility and plan availability.