Move cell to another Column

Hi Centaur. Danie's solution is definitely more robust. But it requires a little more advanced Power Query knowledge. His code doesn't go in the Custom Column box. It goes in the Advanced Editor, which you can get to by clicking View in the ribbon, then Advanced Editor. 

You will want to add his code near the bottom, just above the line that says "in". And where it says "PreviousStepName", you will want to replace that with the name of the step that previously on the line just above the "in". You'll also need to adjust the name of the step in the line below the "in" to NewStep.

So, for example, if your code in the advanced editor looked like this previously: 

let
    Source = Excel.CurrentWorkbook(){[Name="Table6"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Vendor", type text}, {"Invoice Date", type any}})
in
    #"Changed Type"

then you would change it to something like this:

let
    Source = Excel.CurrentWorkbook(){[Name="Table6"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Vendor", type text}, {"Invoice date", type any}}),
    NewStep=Table.FromRecords(Table.TransformRows(#"Changed Type",each if [Invoice date] is text then _&[Vendor=[Invoice date],Invoice date=null] else _))
in
    NewStep

Also make sure that new line doesn't have a comma at the end. But the line that was previously just above the "in" does have a comma.