An understanding of the ubiquitous phenomenon of translocation of electrically charged macromolecules through narrow channels requires an adequate description of polyelectrolyte dynamics, electrolyte dynamics, and hydrodynamics, and the confinement effects from the charge-decorated pores. The biophysics of polyelectrolyte translocation process will be discussed using concepts from polyelectrolyte physics and electrophysiology, against a background of single-molecule experiments. Specifically, the capture and threading of DNA/RNA and proteins through alpha-hemolysin channels and solid-state nanopores under an external electric field, and DNA ejection in bacteriophages will be discussed..