I’m sorry, this might be a very dumb question. I’m fairly new to this, and one of my university classes has asked me to prepare an HTML document and then put it into an empty WordPress blankslate. My question is as follows: ¿can I use the HTML without making changes to the design? ¿Or do I have to change it completely? Thank you!
You can use a php file and them fill it with HTML. It will be the same as an HTML file when it is served but you can also use PHP tags (<?php) in the HTML to process PHP as well.
You really have to change nothing. But getting it to work well with WordPress has additional steps. You may need to break it into smaller pieces like header, footer, etc if you’re making a theme.