Most desktops will have a graphical configuration you can use.

Alternately, you can use timedatectl on distros with systemd.

If you use a non-systemd distro, try hwclock.

Based on my ddg-foo, I was mistaken about being able to configure it via a config file, short of putting it in .profile or some such other thing. That seems hacky though, so I wouldn't recommend it.