How can I display the SSID I am connected to in the Menu extensions area?
The best solution I use for adding the SSID to the menu bar is turning off Apple's menu item and using WiFi Signal app from Adrian Granados:


https://www.adriangranados.com/?q=apps/wifi-signal
https://itunes.apple.com/us/app/wifi-signal/id525912054?mt=12


It's much fuller featured than just displaying the SSID, but it does that job nicely. I am a very satisfied customer of all his Mac apps as they are powerful, well engineered and updated regularly.