Modify Login

Perhaps what I want to do can be accomplished some other way.

I want to be able to notify anyone registering on a site that I expect full names, not handles. I thought dropping in some text would work, but I don’t see where to do that on the wp_login.php page.

Every plugin I look at for login seems to want to modify the graphics, but I am not seeing how to insert text.

I would love some help with this. Thanks.