Setting ownership for files and directories.

The client is undergoing a security authentication review, during which it was recommended to set ownership for files and directories found without an owner. Please provide guidance on how to set ownership.

#find /var -xdev \( -nouser -o -nogroup \) -exec ls -ald {} \;

-rw-rw---- 1 54321 mail 0 May 18 2021 /var/spool/mail/oracle