Hello, Darul Muqarrabin Malaysia,
Thank you for purchasing our theme and for contacting our support team.
You can enable or disable your Newsletter popup by navigating to Dashboard > XStore > Theme Options > Header Builder > delete Newsletters widget.
We have created a video to help you with the process, please watch it in its entirety and follow the steps shown: https://www.veed.io/view/c0ef2233-730c-47c4-a89a-b65e1dca719f?sharingWidget=true&panel=share
This popup is created using Static Block, so you can edit Static Block content from Static Blocks > edit newsletter block.
Don’t forget to enable page builder for the Static blocks https://xstore.helpscoutdocs.com/article/47-static-blocks
We appreciate your business and look forward to assisting you further.
Best Regards,
8Theme’s Team