Modify the Search Bar

Hello,

I am trying to modify the search bar pop-up that displays when the search icon is clicked. I want it to be displayed as a basic search bar exactly as in https://sl.usembassy.gov.

Also, I will like a vertical divider between my social profile icon and the search icon just like in the above website.

Can you please help me with the code? I am new to php

**My site is currently being hosted locally and not yet online