It depends on the specific comic arc. Sometimes she has full control over the transformation and can turn back, but in others, it might be more complicated due to various factors like plot devices or power limitations.
One key element is that Jennifer Walters was an ordinary, hard - working lawyer. Then there was the event that caused her injury. This was crucial as it led to the need for a blood transfusion. And of course, the fact that the blood came from Bruce Banner, the Hulk. His gamma - irradiated blood is what gave her the powers and turned her into She - Hulk. Another important aspect is that she has a different relationship with her powers compared to the Hulk. She is more in control and can still function in a more 'human' way even when in her She - Hulk form.
Well, the back story of the Hulk starts with Bruce Banner. He was involved in some top - secret research on gamma radiation. However, things went terribly wrong when there was an explosion during one of his experiments. As a result of being bombarded by gamma rays, he became the Hulk. The Hulk is a complex character. He has superhuman strength, but Bruce Banner often struggles to control this alter - ego, especially when he gets angry or stressed.
She - Hulk's back story is that she was a normal lawyer named Jennifer Walters. After getting injured, she received a blood transfusion from her cousin Bruce Banner (the Hulk). This caused her to gain similar powers to the Hulk, like super strength and a large, green, Hulk - like form. But she managed to keep more of her intelligence and personality even in her transformed state.
Sure, She-Hulk is related to Hulk. Jennifer Walters, aka She-Hulk, got her powers because of a blood transfusion from her cousin Bruce Banner, who is Hulk. This connection is a key part of their storylines in the comics.