I wanted something that worked in a separate module - let's say module1 that I can call as needed.
If you took the original code offered, and put it in a Standard Module. you could have put Tom's "spittingfire" sub in any Worksheet's Class Module, (with a slight name change,) and used it.
But, to "Call" a procedure means to Call it from another sub. To "Run" a procedure means to use a menu button or the Macro Menu.

You can Run this sub in a Standard module from the Macro Menu

Sub C6_To_P_If_A() 
    Dim Cel As Range 
    With ActiveSheet 
If .Range("A" & Rows.Count).End(xlUp).Row < 13 Then 
 .Range("P12").Value = .Range("C6").Value 
   Else
     For Each Cel In Range(.Range("A12"), .Cells(Rows.Count, "A").End(xlUp)) 
            If Cel <> "" Then .Cells(Cel.Row, "P") = .Range("C6") 
Next Cel
End IF
        End With 
    End Sub