Depends on what you mean. Your question is too generic to give you an useful answer.
My best guess... right click on the column "Remove column", without any detail
I'd recommend that you give more detail of your issue. It's best if you can upload sample workbook demonstrating your row data and your expected outcome (manually created).
Thanks for the feedback and yes in hindsight my question was too generic.
I had created a report bringing in data from various sources for some reason when I went to refresh the data is was just spooling and taking a really long time. When I looked at the source data one of the tables suddenly had a lot of Columns with null values added. Read a lot about unpivoting the data and removing blank rows etc etc. Long story short was too close the data and after sleeping on it just realised i had already unpivoted this data and just needed to go up to an earlier step and remove the blank rows.