On UNIX web hosting, every single file and folder stored has a set of permissions associated with it, which says who is allowed to do what with the file. File and directory permissions can often be changed using your FTP software.
The most common permissions include:
400 r——– files (won’t let you accidentally erase)
444 r–r–r– files (lets everyone read)
600 rw——- files (no one else can read or see files)
644 rw-r–r– files
664 rw-rw-r– files
666 rw-rw-rw- files
700 rwx—— programs and directories
750 rwxr-x— programs and directories
755 rwxr-xr-x programs and directories
777 rwxrwxrwx programs and directories