I use ASCII. Everyone can read it, I can paste it into emails, and I waste no time fiddling around with formatting on a document that will just be scanned for a few keywords and discarded.
They asked me to send them a .doc Word version.
I changed the suffix on my file from .txt to .doc, sent them essentially the exact same file. It opened for them in Word because of the suffix, they were happy and I was then interviewed and hired.
That still makes me smile, these many years gone by.