  The basic theorem of the Lagrangian formulation for general superfield theory
of fields (GSTF) is proved. The gauge transformations of general type (GTGT)
and gauge algebra of generators of GTGT (GGTGT) as the consequences of the
above theorem are studied.
  It is established the gauge algebra of GGTGT contains the one of generators
of gauge transformations of special type (GGTST) as one's subalgebra. In the
framework of Lagrangian formulation for GSTF the nontrivial superfield model
generalizing the model of Quantum Electrodynamics and belonging to the class of
gauge theory of general type (GThGT) with Abelian gauge algebra of GGTGT is
constructed.
