Flash Fill will smartly fill a column based on the pattern of data it sees in the first column (it helps if the top row is a unique header row). For example, if the first column is all phone numbers that are formatted like “2125034111” and you want them to all look like “(212)-503-4111,” start typing. By the second cell, Excel should recognize the pattern and display what it thinks you want. Just hit enter to use them.
This works with numbers, names, dates, etc. If the second cell doesn’t give you an accurate range, type some more—the pattern might be hard to recognize. Then go to the Data tab and click the Flash Fill button. Check out this Microsoft tutorial for more.