I want to know. What is Wifi and which wifi card? is best now in the market. and it is safe to use WiFi device in networking?

wi-fi is wireless networking - the ability to link to a system or PC using tuner signals (as anti to textile cabling). It’s faster and has a greater compass than Bluetooth, and is nonpareil for home or office connectivity. Using a wi-fi falsehood with your PDA or laptop capital that you can portion a band Cyberspace transportation, swap files, or acquire a machine or store area between machine users.

Wi-Fi enabled device such as a smartphones, personal computer or digital audio player can connect to the net when with-in range of a wireless network connected to the Internet. The area of wi-fi is limited, around 2-3 rooms and can be extended.