Type this in front process.applescript

set theString to "Test"

set theseCharacters to characters of theString

tell application "System Events"
	delay 2 -- Time to switch, if running from editor. Can be removed, if running from menu.
	tell front process
		repeat with thisChar in theseCharacters
			keystroke (thisChar as text)
			delay 0.1
		end repeat
	end tell
end tell