Yoga is a physical, mental, and spiritual practice that originated in ancient India. It involves various postures, breathing techniques, and meditation practices that aim to improve flexibility, strength, and balance, as well as reduce stress and improve overall well-being.
In recent years, yoga has gained popularity as a way to alleviate pain and improve focus and concentration. You do not have to be Hindu to practice yoga - that is a myth I think prevents many people from trying it out - they feel their religious beliefs would be compromised. Additionally, there are many forms of yoga. Not all include elaborate poses.