1. Create a new column after the two columns.
2. Name the new column.
3. In the top data cell type: =CONCATENATE(A1,B1) – A1 and B1 are only examples 😉
4. Drag down the top data cell selection to extend series or fill the rest with the new data.
If you need a space between it, you can write it as follows =CONCATENATE(A1," ",B1).
BUT, If you like a Tool which gives you a more easy way for such tasks and other helpful features I recommend you this – http://www.asap-utilities.com/