It's simple with Power Query - make sure your data is a Table to start with, use the Shortcut Ctrl + T. Then click into Data> Get Data from Table to open up Power Query. 

Power Query has all sorts of tools and the more you familiarise yourself with them, the quicker you can work to clean and transform any data problem you may be facing.

Inside Power Query go to the Transform Ribbon.  There is an icon on the left to ‘Use first row as headers’.

 Now close and load back into Excel - Easy!