Show Wi-Fi status in the menu bar
Use the Wi-Fi status icon in the menu bar to switch between Wi-Fi networks, turn Wi-Fi on or off, or open Network preferences.
If the Wi-Fi status icon isn’t in the menu bar, choose Apple menu > System Preferences, then click Network.
Click Wi-Fi in the list at the left.
If Wi-Fi isn’t in the list, click the Add button at the bottom of the list. Click the Interface pop-up menu, choose Wi-Fi, give the Wi-Fi service a name, then click Create.
Select “Show Wi-Fi status in menu bar.”
Four signal bars appear in the Wi-Fi status icon in the menu bar. The more black bars you see, the higher the signal quality.