A Sub procedure is a named block of statements that does something and returns nothing. Every macro you run from the Macros dialog or a button is a Sub.

Code

Sub CleanUp()
  Range("A1").ClearContents
End Sub

• A minimal macro

  Sub CleanUp() Range("A1").ClearContents End Sub → A macro named CleanUp that clears A1

  Run it with F5 or Alt + F8.

• With a parameter

  Sub Report(region As String) MsgBox "Building " & region End Sub → A Sub with a parameter, called as Report "West"

  Parameterized Subs do not appear in the Macros dialog.

• A private helper

  Private Sub Helper() ' only callable from this module End Sub → A Sub hidden from the Macros list

  Private keeps helpers out of the user's way.

• Name Subs with verbs: ImportSales, RefreshPivots.
• Call one Sub from another by writing its name, with arguments after it.
• Keep Subs short and let them call helpers.

• A Sub with arguments cannot be run from the Macros dialog or a button.
• Missing End Sub is a compile error that stops every macro in the module.