Yes, HTML page can be converted to WordPress theme, for this you must be expert in HTML and word press programming. For thsi you need to folow some of the steps which include:
1. Find a template : You can convert any HTML template into a WordPress theme. However, your task will be much easier if you pick a template layout that sticks closely to the core functionality built into WordPress: posts, pages, a sidebar, a header, and a footer. When looking at templates — or coding your own — think about how the parts of the template will translate into a WordPress theme.
These are the steps need to follow for converting any HTML page into word press theme, but it can be only possible if you are well expert in both HTML and Word press. Other wise you must consult a company who is providing WordPress development services For more information visit https://www.chetu.com/solutions/web-development/wordpress.php,