Wireless routers have the option to broadcast or not broadcast wireless networks. It is enabled by default so you can easily find and connect to the Wi-Fi network from other devices. Some users however don’t want their neighbors to see their Wi-Fi networks. Anyone wants to connect to a hidden network have to find the hidden network details first, including SSID (Wi-Fi network name), security type, security key(password for Wi-Fi network). Joining hidden or invisible Wi-fi networks from the Mac is simple. You can follow below instructions.
Click the Wi-fi icon at the top right corner of your Mac screen to pull down the Wi-Fi networks list. The hidden Wi-Fi network can’t be found from the list. Scroll down to the bottom of the list, find and click Join Other Network, see below screenshot.
The Find and join a Wi-Fi network window pops up. Enter the name of the hidden Wi-Fi network, case sensitive, into the Network Name field. Click the Security drop-down menu to select the right security type. Enter the Wi-Fi password into the Password field. Tick the checkbox before Remember this network so you can automatically connect to this hidden Wi-fi network in the future without typing the network name, password. Click the Join button to connect.