Unus Akhilgov explained :
How to select all the words written in capital letters, and
change the font size (eg Times New Roman, 16)?
A task like that involves numerous component parts. You'll need to
break this down into those individual pieces, and then define how
you'll tackle each of them. For example, you'll need to iterate the
document, select individual words, test their case, change their
charactersistics based on that test, lather, rinse, repeat...
Your best hope for help is to identify the parts you're having trouble
with, show what you tried to do, say what happened versus what you'd
hoped/expected to happen, and ask for specific help on the (now clearly
understood) problem at hand.
So, what have you tried, and how has it failed?