To add a download feature to your own website, you can use these methods:

:You can use the built-in "File" block in the WordPress editor to upload a PDF or EPUB and create a download button automatically.

If you are looking for guides to help you build a site from scratch, these are highly recommended:

by John Duckett: A visually stunning guide for beginners.

by Matthew MacDonald: Covers planning, design, and deployment.

by Margarita Kozodoy: A practical guide for using the world's most popular CMS.