Those are PDF files, so they’ll be handled however the visitor has their browser set.
Most browsers have built-in PDF readers now, so the default is to open inside the browser, but all browsers like that will have a download button in their PDF viewer.
There’s no way to force that to behave differently besides re-packaging the PDF file in a compressed archive, like a .zip file.
Perhaps the browser you’re using updated to change its default behavior.
Firefox, Chrome, Safari, and Edge’s default handling of PDF files has been to open them in-browser for at least a year now.
On clicking, the file is neither opening nor downloading. Earlier, the PDF used to open in the browser, but it is still opening but I have to right click and open it in the next tab. How to open it in a single click like before?
Ok, since that is a commercial theme plugin, we ask that you please go to their official support channel, so you can get support from the people who know it best: https://help.hyvikk.com/?envato_item_id=21211407
Forum volunteers do not have access to commercial products, so they would not know why it is not working correctly. Other community members who may have faced your issue might be able to help you, but your best bet is your product’s developer. We encourage you to use the official support venues, as it allows the developers to be aware of issues with their code and gives back to the community in a more robust way.