If you use Hostinger Website Builder, it doesn't matter if your site has already been published or it's just a draft — you can easily preview it from your editor.
Open your website editor and click on the Preview button in the top right corner:
To preview the mobile version of your website, switch to the mobile mode in the top right:
To exit the preview mode, click Back to editor in the top left corner:
Now you know how to preview your site created with Hostinger Website Builder!