Use chmod command in Linux or Ubuntu to set the permission of a file or folder. In Ubuntu all the files and folder have permission to execute, read and write. If the file is of type Directory then it restricts different actions. Only root user has permission to access any files in the system.
There are three types of access permission
chmod 777 /var/www/test
This command is set read, write, and execute permission to "/var/www/test" folder
Same way if you require to apply permission Recursive with -R
chmo d -R 777 /var/www/test