Behavioral therapists treat clients with mental health disorders by helping them identify and change unhelpful or problematic behavior. You can specialize in treating certain behaviors such as eating disorders, phobias, PTSD, etc. If you have any specialization in treating particular behaviors, be sure to include that in your resume.
There are different kinds of behavioral therapy including acceptance and commitment therapy (ACT), cognitive behavioral therapy, dialectical behavioral therapy (DBT), etc. This strong resume does well in illustrating who the applicant has treated, and the methods they have used to treat their previous clients.