I am using Adobe Framemaker 2020 - Unstructured. I wanted to create a PDF output and I link the required documentation to a book but a blank page is getting created automatically after the last page of each section when updating a book. The blank page is created even after deleting it Format > Document > Delete pages
Most probably your files are set to start on a right page. In the book right-click on a file after such an empty page and click Pagination. What is selected? You should change this to Next Available.
Then update the book so that the pagination is updated.
Format » Page Layout » Pagination set to?
⦿ Double Sided
then trailing blank pages cannot be removed by FM's Delete Pages
Here's some info on how the delete blank pages command works, and why it doesn't work sometimes.
I'm in the same camp as Winfried and Bob—I'm guessing that it is your Pagination settings—covered at the very bottom of that post. If your chapters are instructed to start on a right page, but the previous chapter ends on a right page, then Fm is going to add a blank left page, unless you tell it not to.
In the general case, empty pages may appear because they are not really empty. For example, if there are blank lines following the end of your text.
re: …if there are blank lines following the end of your text.
To detect that, elect View » Text Symbols
and look for stray ¶ or § glyphs.