WORDPRESS ADMIN BLANK SCREEN WEBSITE GONE BLANK SCREEN

Never received a solution on how to change and save my text in appearance customize top bar. I was told to update to Highend 1.5 but that didn’t help so I tried to fix it myself. It keeps going back to gray. All other text saves with no problem. So I went into editor theme-customizer.php and added one line of code. Now my website is gone and I can’t access admin/dashboard either. All white screen/blank. I’m trying to find that file in my file manager on Bluehost and don’t know which folder it is to erase that line of code I put in. Does someone know how to access the theme-customizer.php through file manager?