How to reduce the header height

You would need to customize the theme. The best way to do that would be to use a child theme to add your own CSS. You could also use it to add padding to the top of your logo to put it in the middle of the header area versus making the header area smaller.

It’s hard for me to be much more specific without a link to your site.

Hello sir i am thankful to you for your quick reply. i agree with you sir to make its child theme so for this purpose i use custom css manager but i donot know what code i should write in the custom css manager plugin to adjust the height and width of the header.
please give me some piece of code or any hint in CSS file to trace that function and change from there.
thanks and best regards

There is no fixed height, or coded minimum height on the header area. The size of the header area is determined by the stuff inside of it, like padding and margins.

I could provide you with CSS that you could paste into your plugin, but I’ll need a link to your site so I can figure out what that code is.

Once again thanks for quick reply. my website is https://www.hvacszone.com/ and here you can see the seperator line of email, phone and address are more in vertical height than the height of logo image, secondly sir when u go on bottom there you will see the text color of pages is something odd. i made it blue but it does not show blue here and show as you see in footer 1.
thanks in anticipation sir.