What is the best way to store and load HTML data?

I am building a simple portfolio website for myself and I faced a problem. My portfolio item (project) model contains HTML template (large description with text formatting and images). What is the best way to store these templates? And what is the best way to implement loading them in browser?

For the second question my idea is to create /portfolio/index.html and use routes like https://mywebsite.com/portfolio/%projectname% to get projectname and load all content using XHR.

P.s.: I decided to use vanilla JS on client side to make pages faster and lighter.