Refresh the page when a form is submitted

I have a _header.php file which is included in all my pages and contains the usual header, nav, logo, etc. I have added a ‘log in’ button to it which opens a modal containing the login form. It works fine so I can now easily log in from any page. But, I want the page I’m currently on to refresh so the changes appear now I’m logged in.

What’s the best way to achieve that?