A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Others will undoubtedly come up with a Microsoft 365 formula solution, or a Power Query solution. In the meantime, here is a short macro:
Sub StackData()
Dim c As Long
Dim s As Long
Dim m As Long
Dim t As Long
Application.ScreenUpdating = False
t = 2
For c = 2 To 4
m = Cells(Rows.Count, c).End(xlUp).Row - 1
Cells(t, 6).Resize(m).Value = Cells(1, c).Value
Cells(t, 7).Resize(m).Value = Cells(2, c).Resize(m).Value
t = t + m
Next c
Application.ScreenUpdating = True
End Sub