To set the system wide default umask for all user you need to make the below configuration in your server.you need to add the below configuration in /etc/profile to have newly created directory having 755 and file having 644 permission.

umask 0022

Noe logoff the session and check the newly setup umask using usmak command.

Note:Note that users may still override umask in their own ~/.profile or ~/.bashrc or similar, but (at least on new Debian and Ubuntu installations) there shouldn’t be any overriding of umask in /etc/profile or /etc/bash.bashrc. (If there are, just remove them.)

Hope it will help you.