How to make author box like this & add after every post?

I’ve not tested your code; but assuming it’s correct and working well, edit your single.php file and insert this code just after the point where you end your post content and before the Comment Section starts.

I’d suggest to write this Author Box code in a separate file and then use get_template_part to insert the Author Box section in your Post. See this function Reference page if you’re new to the get_template_part function.