The most important thing is to wear something that you are comfortable in. The last thing you want during a yoga flow is for
your clothing to be a distraction or to make you feel uncomfortable.
Wear clothing that won't restrict your movement. Leggings can often be a goto for yogis. Additionally, I would encourage female yogis to wear a sports bra, you will find that metal, in the back of a bra can be quite uncomfortable in some poses. Tops should be comfortable and not so lose that you will feel exposed in inversions.