Q: I accidentally erase wifi from interface

Not sure what you are referring to, but perhaps this...

System Preferences > Network > select Wi-Fi in the sidebar > check mark Show Wi-Fi status in menu bar.

AirPort Utility app is located in Utilities folder inside of Applications folder.

Are you asking a question about an AirPort router.....the devices that you see below that we support in this forum.....the AirPort Express, AirPort Extreme and AirPort Time Capsule.......

Or, are you asking about the WiFi setting in the Network settings of your MacBook Pro?

Or are you asking about the WiFi menu at the top of the Mac's screen?

Open Network

Click on the small + (plus) button at the bottom of the connection list

For Interface, select Wi-Fi

For Service Name, type in a name that you want to use, like WiFi, for example

Click Create

Then, you may need to reinstall the El Capitan operating system on your Mac.

Please post over in the support forum for El Capitan for more information, as this is not a question about an Apple router. The link is just below.

OS X El Capitan