in reply to
How can one create a folder B in D drive and save results in a text file inside B using perl script?
You've been here intermittently since 2009 but I have yet to see you ask a question that's not readily answered in one or more basic texts -- "Learning Perl" and the resources at learn.perl.org come to mind -- when those are seen as sources of more than mere code samples.
Your remark about searching for code in the docs suggests that you misunderstand the code in docs as a mere source of code to cargo-cult rather than as samples illustrating the main text.
And in this case, the logic of your code leads to the inference that you expected the directory "B" on drive "D" to auto-vivify. Windoze doesn't work that way, highlighting your failure to understand your OS.
- - for lack of effort