I just deleted my wifi from my Macbook because it was not working. How do I get my wifi back?

A website told me to delete the wifi option off of my network preferences because my wifi was not working. After that, I followed the directions and restarted my computer. I went back to network preferences to add the wifi back, but it was no longer an option. Now I have NO wifi and can't find any website or answer to how to add the wifi option back to my network preferences. It totally disappeared. HELP