In Mortal Kombat (2011) and Mortal Kombat X, moving foward makes you walk a normal speed, while tapping the stick in that direction twice, you dash foward and cover about twice the distance. How can I replicate this in my fighting game using the right arrow key?

Thank you so much

Ok i need to think tjis through

You should share the project and link so we can tell you a specific way to do it for your project.

One way you could do it though is like the below. This is probably an inefficient way to do it though by itself as it adds a new forever loop.

when green flag clicked
forever
set [presses v] to [0] // Holds how many presses there are
wait until <key [right arrow v] pressed?>
if <((timer) - (lastPress)) < [1]> then // Get the time since the last press
set [presses v] to (2)
else
set [presses v] to [1]
end
wait until <not <key [right arrow v] pressed?>>
set [lastPress v] to (timer) // Save the time of this press
end

Just a side note on imfh's post.
The boolean that checks the difference between the timer and the lastPress variable probably shouldn't be compared to 1, as that would give an entire 1-second window to double tap the key. I would try somewhere between 0.2 and 0.5 seconds instead.
Just my opinion.