Hello, @IP,
First of all, you have to create a block in the Dashboard >> Static block and set the content in it as you need. After that navigate to the Dashboard >> XSTORE >> Theme Settings >> WooCommerce >> Single Product Builder >> and add the custom HTML widget in it then choose the block you created see the image: https://postimg.cc/ZBDTBG0S then save settings and check back to your site after clearing the browser cache.
Regards 8Themes Team.