Kali Linux and Parrot OS are developed on Debian standards, used for penetration testing. Both operating systems were released in 2013.
Kali Linux needs a RAM of 1 GB minimum whereas Parrot OS needs lesser RAM about 320 MB. Kali Linux needs a graphical card since it needs graphical acceleration whereas Parrot OS does not need a graphical card.
Kali Linux follows simple interface such as Gnome desktop interface and Parrot OS interface is built on Ubuntu-Matte-Desktop-Environment. Kali Linux has all tools required for hacking and Parrot has all tools present in Kali and also has its own tools.
You can master these skills and become proficient in Linux operating system by enrolling in an industry-recognized Linux Certification Training.
You can watch this video to know more about Kali Linux and Parrot OS: