To underline words in iPad, first, open the iPad Mail app and then compose a new email message. Then, press and hold your finger on top of one of the words until the "Select/Select All/Paste" menu pops up. After that, press the arrow on the right side of the "Cut/Copy/Paste" menu to scroll over to "U" button. Next, press the appropriate button to make the text underlined. For more information, visit the howtoforipad.com website.