I have a code that I need to insert into the HTTP header of my website to make Google Fonts work again.

My Google Fonts aren't rendering on one of my simple websites (http://ceobusinessalliance.com). I coded it from scratch using Bootstrap and WordPress. They were rendering before but are no longer. According to the error in the console and Google's support page (https://developers.google.com/fonts/docs/troubleshooting), I need to make sure Access-Control-Allow-Origin:* is in the header.

What is the function I use to do this? I'm not a very strong WordPress developer. I mostly work with developing themes.

Edit: I am using Chrome.