Okay for future reference this could be one answer:
Check the Autoload and Kernel path by $Path.
One can then add the desired PATH (in this case /Users/gkdgoutam/Softwares/HEP_Softwares/MT ) inside
/Users/gkdgoutam/Library/Mathematica/Autoload/init.m
For example:
$MTPath = "/Users/gkdgoutam/Softwares/HEP_Softwares/MT"
If[Not[MemberQ[$Path,$MTPath]],$Path = Flatten[{$Path, $MTPath }]];
Then add the Autoload/init.m in Kernel (if not done already) i.e. in
/Users/gkdgoutam/Library/Mathematica/Kernel/init.m
by adding the following:
Get[ToFileName["/Users/gkdgoutam/Library/Mathematica/Autoload","init.m"]]