In windows it is possible to change
administrator username for security reasons. Is it possible to change
root username in Linux too?
While it's technically possible, it is probably not a good idea. You would have to audit all the code on your system to check if any of it has the
root user name hard-coded.
While the recommended practice for e.g. shell scripts is to check the user ID (if it's zero, you are
root) or check for the actual privilege you require (if you can write a file where you want to, who cares which precise user you are running as) but not all programs adhere to the recommendation. (In fact, the installers and/or packaging scripts for many popular commercial software packages contain some truly atrocious shell scripting.)
A hack which was employed by BSD once upon a time was to have a duplicate user in
/etc/passwd with the same user and group ID, but a different user name (and a different shell, which was the purpose of this exercise); they called this user
toor. This hardly helps for your particular use case, but may still be useful as guidance. The fact that this (generally) worked is a good indication that you could simply rename
It's possible to change the name of the root account: edit your
passwd file. You'll break stuff, because various applications assume that the root account is called
root. (That's why it's called a “root account”, after all.)
Renaming a system account isn't supported any more than renaming some random system file is supported, or applying
rot13 to a system file.
There is zero security benefit in renaming the root account. It will not help against any exploit. Root exploits work by causing a program running as root to execute code that it shouldn't execute. The name of the account is completely immaterial. It's like painting your front door a different color: it won't help you against burglars, you need to work on having a good lock, barring your windows, etc.