This feature was only open on certain i-OS platforms while running the test. After the test, Facebook has unveiled this feature worldwide. To get this feature, go to the 'More' tab and select 'Find WiFi'. And after that, the feature will find out if the user has a WiFi network nearby.
However, this feature will not get all possible WiFi connections. Only people who want to share their WiFi network with Facebook will find this feature. All i-OS and Android users in the world will get this feature in phases. On the other hand, Facebook has said that the number of users currently is 200 million