As we wont compile code in perl, But in Perl why do we need makefile.pl ?

For the same exact purpose as when you did "compile code", the purpose doesn't change

Are there any differences between the make command in unix and the makefile.pl concept in perl ?

Yes, the documentation explains the difference

Are these interview questions (for a job) of homework question (for a grade)?
make ... To prepare to use make, you must write a file called the makefile
ExtUtils::MakeMaker - Create a module Makefile
Module::Install - Standalone, extensible Perl module installer
Module::Build - Build and install Perl modules