There are many variations. Nadi Sodhana - extending both the exhalation and inhalation through nostrils alternately and using the throat. The control of the air flow done by finger mudra. Sitali - Curl up the tongue to form a tube and one breathes in through this tube. As you breathe in lift up your head.
Inhalation is down by lowering the head to complete the cycle.
Kapalabhati - Breathing is done faster and at the same time use only abdominal breathing. Breathing becomes rapid, short and strong. Bhastrika - This involves breathing using abdomen. Breath in through one nostril and strongly breath out thro' blocked nostril. But you must be clear that each of these techniques have different benefits and application.