In views how to merge two columns?
You first need to add one more field in your view i.e Global Custom Text.

After that you need to merge your two fields result in this field output using Replacement patterns

As in attached screenshot, I am merging nid and first name field in global custom text field output.

You also need to exclude "Uploaded covering letter" and "Uploaded e-book" field from output using Exclude from display attribute. You need to checked this check box for both the fields.