Problem with .php file

Well I think it’s the header .php but I don’t know enough about coding to be sure.

In the left of the header of my site you will see a small piece of code https://onlineprofittools.com/blog/ on the home page here you see it says
class=”home blog”>

On the about page it says class=”page page-id-45 page-template-default”>
and so it changes with each page.

I’m trying to find out why it’s there and how I can get rid of it

Any help greatly appreciated