How do I delete pdf, and will annotations keep?

Hi,
I’m not clear if I’m deleting the PDF by just pressing the back button and getting rid of pdf-name on display in the “add documents” bit of the page. How do I delete a PDF I’ve added?

Also, after I add the annotations (both text and box annotations), if I delete that PDF, will my annotations persist?
Kindly clarify.

Many thanks,
Brindha