if I understand this correctly, I can think of three different ways to do this, depending on what you want the dimension to look like.
If you're using hole wizard, find the icon for "hole callout", it's in the annotations toolbar (or insert, annotations, hole callout). It looks like a c'bore & diameter symbol. Then click that on the hole and you're settings in holewizard determine the callout. You can do a search for callout.txt and modify the way the holes are called out in this style of dimensioning.
otherwise, dimension the hole, overwrite the dimension by copying and pasting over the dimension with the desired text, and click ok. One advantage of this is that the leader always points to the center of the hole. You're basically turning a dimension into a note.
If you're trying to do a little bit fancier hole notes, example: bold, italics, underline, certain size fonts, layers or colors, certain typed text -- lookup "Dimension Favorites" in the help menu. It's worth the few minutes it takes to read up on them. Few people seem to use dimension favorites but they work great for all kinds of situations in drawings, and you can save them as if they were a separate file so you can re-use them again and again on other drawings or even other computers. When you make a simple dimension in a drawing, there's five little icons on the left, at the top of the feature manager window, it's the dimension favorite icons. you may be able to figure them out without the help menu, they are pretty simple.
I'm sure there's other ways too.
Good Luck