try this
Option Explicit
Sub main()
Dim data As Variant
With Range("A1").CurrentRegion
data = .Resize(.Rows.Count - 1, 4).Offset(1).Value
End With
ReDim wynik(1 To UBound(data)) As Variant
Dim i As Variant
For i = 1 To UBound(data)
data(i, 3) = Format(data(i, 3), "yyyy-mm-dd")
wynik(i) = Join(Application.index(data, i, 0), "_")
Next
Range("E2").Resize(UBound(data)).Value = Application.Transpose(wynik)
End Sub
3
solved Macro concatenating strings + number + date