There are many default keyboard shortcuts* set up on your system.
Find the general ones in start Menu → Settings → Keyboard → Application Shortcuts tab,
and in Menu → Settings → Window Manager. You can also configure/override your own,
to make your workflow more convenient, fluid, natural, and intuitive.
These are desktop keyboard shortcuts that work with all windows. Additionally, every
specific application has its own set of configured shortcuts. You can see them on the
right side of the application menus.
* Keyboard key combinations that issue a specific command or functionality.