Several Eastern influences that were mostly in India like Jainism, Buddhism, and Hinduism incorporate yoga into their religious practices. There would be yoga gurus (an expert or master) in India who consulted with individuals about their aspirations or spiritual goals.
In Western culture, yoga's mostly seen as a form of exercise or an easy way to become more flexible. Although it produces excellent results, yoga is much more than that.
Buddhist monks are oftentimes associated with meditation but anyone can practice it. Within yoga, the instructor or whoever is practicing focuses on breathing a lot. Poses require certain breathing patterns for optimal peace of mind and heart rate control. The strong flow of oxygen relieves tension, releases anxiety, and clears the mind.
There are several poses one could use for meditation that have been linked.
As one article summarized, meditation clears out mental pollution/de-fogs the mind. In a way I look at it as smudging from the inside out; you can release bad energy by meditating.
I prefer to do yoga outside in warm weather for optimal mood lifting. I've never genuinely meditated before but I do see it as an opportunity to deeply reflect.