Hi, you can reference a worksheet using
Sheets("Sheet2")
Where sheet2 is the tab name
or
Sheets(2)
Where 2 is the index, or position of the sheet in the worksheet
or
Sheet2
Where Sheet2 is the name of the vba object of the worksheet (in the project tree)

So using the first method:
Macro_show_data()
Sheets("Sheet2").ShowAllData
End Sub