in my testing application after click on download PDF using cypress , typescript getting below window which is not a browser popup. unable to detect any element using cypress locator as it is not a browser popup. I need to select "save as PDF" by click on PDF drop-down button present in the popup. Unable to perform any action on PDF drop-down button.

You won't be able to interact with OS UI with cypress.

then is there any way to handle this popup ?

I think the main thing is what are you wanting to test here? Is this getting generated from trying to print a page on the browser?

my aim is to download the pdf after downloadPDF.click(). but after this click operation this popup coming up.

Yeah if frontend doesn't handle that download differently then there's no way to download the pdf this way using Cypress.

but when I am trying to the steps manually on my application getting browser print popup when trying by cypress getting this native popup.

It's just printing the current browser page though right? Why test that? As far as why you would get different popups when running manual vs cypress I'm not sure.