How to create a package Oracle Report builder

What kind of package?
You can define package or set of function in the schema
taht the report will run and call the functions in the SQL
of the Report. They should be functions - return only one value.

The call of a pacge function is the same as the single function, but
should be prefixed by the package name.

It is possible (and quite eay) to create a package in a Oracle Report (or in a *.PLL library that is attached to the report) that contains a function.  Then that function could be called from any program unit in the report.  But you cannot call this function then in a query in the report.

So, are you sure that you want the package to be created in the report, or should the package be created in the database instead?  This would allow the function(s) in the package to be called by any query in any Oracle Report (and/or an Oracle Form or anything else that connects to the database).

To create a package in an Oracle Report, just go to the Program Units node, then under Navigator, choose: "Package Spec" and define the specification, then choose: "Package Body" and create the body of the package.