Difference between a sub and a function?

A Sub Procedure is a method will not return a value A sub procedure will be defined with a Sub keyword
Sub ShowName(ByVal myName As String) 
Console.WriteLine (My name is: & myName)
 End Sub 
 A function is a method that will return value(s). A function will be defined with a Function keyword 

Function FindSum(ByVal num1 As Integer, ByVal num2 As  Integer)  As Integer 

Dim sum As Integer = num1 + num2 

Return sum 

End Function