Some cameras use WiFi to remotely stream and record video, but there are many options on the market which will record footage on SD cards for later review. You can filter our hidden cameras with SD card storage to find a good choice for any purpose.
These are not common on the market, but alternatively you can also find cameras with Bluetooth and Cellular connections. Bluetooth cameras are suitable when you need a very short-range remote streaming functionality to a nearby phone or PC. Hidden cameras with cellular connections will use mobile networks to stream video or send notifications, and are best for surveillance of remote properties such as cabins or boats where it’s difficult to get a reliable WiFi connection.