How to control panic attacks and Exam related Anxiety

As the title says ..... I'm asking this for my sister { dropper } who is in kota preparing for jee . I tried my best to help her but she has like severe or next level anxiety and ngl I don't even know what should i tell her cause I never had panic attacks or exam related anxiety . So , If anyone knows how to deal with all this then please drop your advice/suggestions . Thank you :)