Index HTML File

Hey there, I have recently had to take control of a website which belongs to the company I work for. I'm very new to Cpanel (Only really used wordpress recently - notepad way back when) I am just wondering if I could possibly get some pointers on something. I have been asked to remove the purple wrap around "takeover" graphic from our webiste however i cannot find the index html file anywhere. I have found Index.php but no html. Is there anyway of seeing where it actually is? Many thanks! Scott