The original directory permissions are 777 or ‘rwxrwxrwx’
The original file permissions are 666 or ‘rw-rw-rw-‘
The umask value differentiates, the original and default file or directory permissions.
666 777 ----------- original permissions
-644 -755 -----------Default permissions
022 022 -----------Umask value
We can see that, whenever we subtract the default permissions from original permissions, we get the umask value.
From this analysis, we can conclude that the umask value will decide the default file and directory permissions.
To change the umask value the command is #umask
But this change of umask value is not permanent whenever the system reboots we loss this change.
To change the umask value permanently edit the /etc/bashrc file
Edit the 68th line to change the umask value permanently.