How do I underline the space AFTER a word in Microsoft Word?

I know about the _ key, but that line is placed below the line that underlines words and so it looks stupid. Is there a way I can continue the underline after the end of the word all the way to the end of the line. For some reason, Microsoft Word will not underline the spaces AFTER the end of the word/character. I am trying to complete a printable doent on my computer.