create or replace procedure my_proc(
  insert_table my_package.my_table
)
as
begin
  ...
end;

create or replace package my_package as
  type my_record is record
  (
  	FIELD1 NUMBER(11),
	FIELD2 VARCHAR2(200)
  );
  
  type mt_table is table of my_record;
end my_package;

using (OracleCommand command = new OracleCommand())
            {
                    ...
                    OracleParameter parameter = new OracleParameter();
                    parameter.ParameterName = "insert_table";
                    parameter.OracleDbType = OracleDbType.RefCursor;
                    parameter.Value = table;  //DataTable
                    command.Parameters.Add(parameter);
                }
                command.ExecuteNonQuery();
            }