In order to make your app a PWA, Progressier requires you to upload a custom service worker file to the root of your WordPress site.

We can't provide you with a one-size-fits-all set of instructions as there are a lot of different ways to achieve this depending on how you manage your WordPress setup.

But here are some common examples:

By adding the file to your public directory

From: https://stackoverflow.com/questions/43741499/wordpress-allow-files-in-site-root-to-be-accessed

By connecting with SFTP or SSH

From: https://wordpress.stackexchange.com/questions/371351/how-can-we-upload-file-to-root-directory-of-wordpress

By using cPanel

From: https://kinsta.com/knowledgebase/how-to-upload-html-file-to-wordpress/#upload-cpanel

By using WP Filesystem

From: https://wordpress.org/support/topic/how-to-add-files-to-root-directory-from-wordpress-plugin/

By using a file upload plugin:

From: https://kinsta.com/knowledgebase/wordpress-file-upload/