Text >> Replace All will replace all instances of a word or number if they are separate text objects.
But if there are several instances of the word or number in a body of text, it only replaces the first one it finds. So if you've consistently spelled something wrong – or want to change a list of numbers for example, it only changes the first occurrence, not the whole lot.
Not a big deal because you can do it sequentially using the Find – Replace boxes.