If you've started creating your website on Hostinger Website Builder and would like to use WordPress (or another CMS) instead of Hostinger Website Builder, you simply need to delete the website built with the builder and set up a new website from scratch using another CMS.
A deleted website cannot be restored; all its content is lost permanently
If you have an email service set up for your domain, make sure to create a backup of your emails, as deleting the website will also delete emails
In hPanel → Websites, delete the website that you've created:
Then, add a new website to your hosting plan and choose WordPress (or another CMS) as your preferred website-building platform. If you select WordPress, to finish the setup, create a WordPress account, choose the preferred plugins and website template, and insert the domain name that you've previously released by deleting the website built with Hostinger Website Builder.