In the 20th century, a development of haṭha yoga, focusing particularly on asanas (the physical postures), became popular throughout the world as a form of physical exercise. This modern form of yoga is now widely known simply as “yoga”. Wikipedia
In the western world, Hatha yoga has become a commonly performed form of yoga. Hatha Yoga classes would be more basic and gentle, with a focus on alignment and the physical and mental benefits of each pose, making Hatha the ideal choice for a beginner yogi.