No, it is not necessary to have an internet connection to use the Wi-Fi feature of the trail camera. The Wi-Fi feature allows you to connect your smartphone directly to the camera's network. 

Yes, multiple users can connect to the Wi-Fi network of the trail camera at the same time. However, the performance of the camera may be affected if too many users are connected simultaneously. 

A Wi-Fi trail camera utilizes a wireless local area network (WLAN) to send images and videos to a smartphone, tablet, or computer for remote viewing. This type of camera does not require a cellular service plan, as it can connect to a router or access point within range. On the other hand, a cellular trail camera uses a cellular service plan to send images and videos to a smartphone, tablet, or computer. It is able to embed GPS coordinates within the image, making it easier to locate the camera. Furthermore, cellular trail cameras are able to send images and videos to a remote location with no need to physically retrieve the device. This feature requires a cellular service plan with data, which can be costly. Overall, a Wi-Fi trail camera is best suited for connecting to a local router or access point, while a cellular trail camera is best for sending images and videos to a remote location. 

Yes, you can control the trail camera using your smartphone through Wi-Fi. You can change the camera settings, view the live feed, and download the photos and videos captured by the camera. 

The Wi-Fi signal of the trail camera can reach up to 100 feet in an open area. However, the signal strength may vary depending on the obstacles and interference in the area.