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Under Linux, permissions are assigned to users and groups. Each user can be a member of different groups, and membership in these groups gives the user specific, additional permissions. Each file and directory belongs to a specific user and a specific group. So the permissions for users and groups that defined a file are also defined for the respective owners. When we create new files or directories, they belong to the group we belong to and us.

kali@kali[~]$ ls -l /etc/passwd

- rwx rw- r--   1 root root 1641 May  4 23:42 /etc/passwd
- --- --- ---   |  |    |    |   |__________|
|  |   |   |    |  |    |    |        |_ Date
|  |   |   |    |  |    |    |__________ File Size
|  |   |   |    |  |    |_______________ Group
|  |   |   |    |  |____________________ User
|  |   |   |    |_______________________ Number of hard links
|  |   |   |_ Permission of others (read)
|  |   |_____ Permissions of the group (read, write)
|  |_________ Permissions of the owner (read, write, execute)
|____________ File type (- = File, d = Directory, l = Link, ... )