As far as I know scanning WiFi networks around is Limited to only one old app Apple made
Use AirPort Utility to manage your Wi-Fi network and AirPort base stations, including AirPort Express, AirPort Extreme, and AirPort Time Capsule — right from your iPad, iPhone, or iPod touch. See a graphical overview of your Wi-Fi network and devices. Change base station and network settings...
apps.apple.com
When you download it you have to go to Settings > Airport and turn on switch for WiFi Scanning
And then open app and run scan via upper right “WiFi Scan”.
This will give you details about current network and all around.
RSSI, SSID, MAC address and WiFi channel
Edit: after you use it and plan to stop - disable this WiFi scanning switch, it was draining battery in background in the past