How do you call in sick?

Just curious as when I'm ill I worry so much about how to word the message to work or what to say, while other people seem to call in sick all the time.

How do you word the message if you text your boss to say youre too ill to go to work? How specific do you go?

I have to feel like I'm dying to call in sick just because the anxiety I get from writing the text is too much!