vba to fill header value to apply to below cells of nonblank

How about this,

Sub dave()
  Dim a, c As Long, r As Long
  Dim x()
  Dim i As Long, j As Long
     
     With Sheets("FILLDATES")
        a = .Range("C2").CurrentRegion
        r = UBound(a): c = .Range("C2").CurrentRegion.Columns.Count
     End With
        ReDim x(1 To r, 1 To c)
          For i = 1 To c
             For j = 1 To r
               If i = 1 Then
                  x(j, i) = a(j, i)
               ElseIf a(j, i) <> "" Then
                  x(j, i) = a(1, i)
               Else
                  x(j, i) = a(j, i)
               End If
             Next j
          Next i
     With Sheets("OUPUTLIKE")
       .Cells.Delete: .Cells(3, 1).Resize(r, c).Value = x
       .Rows(3).Font.Bold = 1: .Cells(4, 2).Resize(r - 1, c - 1).Interior.Color = vbYellow
       .Columns(1).Resize(, c).AutoFit
     End With
End Sub

No problem, remember to say thanks.