Raama,
Think about it - we would need rather a large keyboard and lots more fingers than what we've got.
Fonts containing common ligatures are not hard to find, but will still require two or more fingers to click those keys.
Such keys are still clicked in combination and in sequence
Like, press and hold one or more of them modifier keys - Crtl, Shift and Alt.
and then, but not before else all labouring is in vain, press, and release, one of them letter keys.
These days, with the likes of Windows 10, you can simply speak nicely to your computer to get the job done.
However, people do tend to feel a bit silly when talking to nobody, so confine Cortana to the bit bucket.