CUSTOMIZE HEADER FOR WORDPRESS BLOG

Hi all,
I have my WordPress installed at my website at https://chemtopper.com/blog/

I wish to change the header of the blog further to a header.php file which includes the images and the links I require on header of my my blog. I have placed this header.php file in the include folder on my website so that the same can appear on all the pages.
I would like the same header to appear on the blog also.
I need to know where and how to put the link to this header,php file in the wordpress blog coding so that it can be displayed on all the pages. I am sure any theme developer would be able to help me out in this.
Thanks for your help.