How to enable the settings  that allow customers to cancel and existing order even before the order gets delivered?

Any Updates on this

Sorry Patryk.. I just now found the cancel button.

It's setting in the admin panel. If you don't know where you can find some setting, it's also good to go to Admin panel -> Configuration -> Settings -> All settings (Advanced). In the filtering text box, you can type one word of the setting, related with it and you will probably find what you are looking for.