You declare a variable to specify its name and qualities.
You use the statement
Its location and contents give a variable its qualities.
For information on how to make correct names, see Declared Element Names.
Local and member variables
A local variable is a variable declared in a procedure. A member variable is a member of a declared type. You declare it in module scope. It can be a member of a class or structure, but not in a procedure internal to that class or structure.
Shared and instance variables
Declaring data type
Qualities of declared variables