How to call a separate html page on the top of a php website

How does a php program website call a separate html page wordpess on the top? How does it call an independent html page on the page? I want to call an existing separate html page on the top of wordpress. how can a page be implemented? if some CSS is used to modify html, direct code may cause page dislocation, therefore, you can only call the PHPcode & lt;! of the html page ;! How does a website of the DOCTYPEhtmlPUBLIC & qu php program call an existing html page on the top?
How does wordpess call an independent html page on a page?

How can I call an existing html page on the top of wordpress?

Because html is modified and some CSS is used, direct code can cause page dislocation, so html pages can only be called.

PHP code

  
  <? Php global $ page, $ paged; if (is_home () {$ options = get_option ('xiaohan _ options'); echo ($ options ['indextitle']);} else {wp_title ('|', true, 'right'); bloginfo ('name'); if ($ paged> = 2 | $ page> = 2) echo '| '. sprintf (_ ('Page % s', 'xiaohan '), max ($ paged, $ Page) ;}?>
  Post_excerpt) {$ description = $ post-> post_excerpt;} else {$ description = utf8_CsubStr (strip_tags ($ post-> post_content), 0,190);} $ keywords = ""; $ tags = wp_get_post_tags ($ post-> ID); foreach ($ tags as $ tag) {$ keywords = $ keywords. $ tag-> name. "," ;}} elseif (is_category () {$ description = strip_tags (category_description (); $ categoryname = get_the_category (); $ keywords = $ categoryname [0]-> cat _ Name ;}?>
   
  // The following line is the code. if you want to insert the code in this position, you can only call the html page if you modify html and directly use the code to cause page dislocation.