Trauma affects us physically, emotionally, and psychologically in ways, we might not fully comprehend. Trauma puts us in a constant state of hypervigilance or fight and flight in such a manner where we constantly feel like we have to be on guard and are at the edge. This affects our ability to stay in the present moment and experience the full range of human emotions. If you want to work with people that are dealing with trauma in your yoga practice, then you will have to certify yourself as a trauma-informed yoga instructor since the requirements and needs of clients are very sensitive and different from standard yoga and you have to be properly equipped and trained to handle them. For this, you need to enroll yourself in a couple of courses and training programs from renowned institutes that offer it like the Marianne Wells Yoga Teacher Training and so on.
The purpose of yoga is to help us come to the present and pay attention to our breathing and bodies. This might be an easier practice for people that have not dealt with trauma, but for people who have been affected by traumatic events in life, this can be difficult.
You have to essentially create an environment where you teach people that they can let down their guard and trust their bodies. This can be a very overwhelming process for some people, and you will have days where people might cry or get emotionally overwhelmed as a result, and being a trauma-informed yoga instructor will require that you help these people during those moments and help them slowly learn to feel grounded. It can be a very emotionally taxing job most days, but when you see results, it can be worth all of the hard work on your end.