I usually setup my umask value in my login rc. For KSH, that is in "$HOME/.profile". For CSH, "$HOME/.login". For Bash, "$HOME/.bash_profile". That works well because your login shell will be the parent of all the sub-processes you create, and receive a copy of that environment.

"umask 022" or "umask 0022" is the default when not specified. This equates to "chmod 644".

# umask
0022
# touch test
# ls -l test
-rw-r--r--    1 root     root            0 Apr  3 10:04 test
[download]

I normally set it to "umask 002", allowing members of my group to have write access to anything I create, resulting in "chmod 664".

# umask 002
# umask
0002
# touch test
# ls -l test
-rw-rw-r--    1 root     root            0 Apr  3 10:06 test
[download]

Verify what is currently active with "umask" and no arguments.