Block themes require a style.css file and a templates/index.html file. A block theme that supports WordPress 5.9 or older also requires an index.php file in the root folder.
You need to place all HTML template files inside the templates folder. If you place template files in the wrong folder, the theme will not load correctly.
Template part files are optional. If they are included, they must be placed inside a folder called parts.
The theme.json configuration file is optional but strongly recommended. Learn more about theme.json.
In addition to the required files, the theme can include a theme.json, a functions.php file, and any additional PHP files, CSS, images, or JavaScript to enhance the theme.
Example file structure:
