Exit Sub on error - public or private?

Is it possible that once an error in the code occurs, the routine is terminated, instead of showing the written vb code?
My concern is that the user never get to touch at the code, although I recognize that this happens because of the lack of robustness of my code...

Yes, by adding error handling to your procedures you can "handle" the error instead of letting vba break and stop on the line of code that generated the error.

VB Code:

Option Explicit
 
Private Sub Workbook_Open()
    On Error GoTo MyError
    Dim str As String
    str = "Meow"
    MsgBox str / 0 'Generate a divide by 0 error
MyErrorExit:
    Exit Sub
MyError:
    Msgbox Err.Number & " - " & Err.Description
    Resume MyErrorExit
End Sub

Should I insert this code in every Sub? Is there some way to make it public, for every user form I have?