Abstarct: In this thesis, quantum transport phenomena in a double quantum dot under different regimes of bias, coupling, and decoherence are theoretically investigated. The main focus is on the relationship between the Hamiltonian structure of the system, the quantum dynamics of charge and spin states, and measurable quantities such as electric current and shot noise. Using quantum rate equations and the density matrix formalism, the difference between coherent and incoherent transport is analyzed, and the validity conditions of each descxription are compared. Phenomena such as spin blockade, photon-assisted tunneling, electron pumping, and the role of nuclear fields in breaking spin blockade are also examined. The results show that the double quantum dot system provides a suitable platform for studying quantum coherence and implementing the basic concepts of charge and spin qubits in solid-state architectures.