Can't edit HTML in Wordpress

Question

I recently started using Wordpress. Since my WordPress skills are not very good, I cannot do some things with just WordPress. Therefore, I need the ability to edit the HTML code of the page. In Stackoverflow, I did not find an answer on how to edit html code, there is only how to edit page.php. When among the pages I find the one that I want to edit and click the 'edit' button I see this

P.S. Maybe there are some mistakes in the question, I am using a translator

Answer 1

等待大神答复