I'm looking into the future here and will tell you about the workload of a forensic psychologist after you are finished with school. The thing to note is that forensic psychologists are generally required to have a doctorate degree and be a fully licensed psychologist. They also receive specialty training and certification in forensic psychology to gain a solid knowledge base of forensic issues and history, case law, and providing testimony. Masters level psychologists' roles and scope of practice are often limited, and this can vary by state. I know in Michigan where I practice a person with a masters degree must always practice under the supervision of a licensed psychologist and cannot engage in any independent forensic work. We have two masters level psychologists where I work. They are very helpful and in this particular role provide psychological test administration and scoring when asked and can also consult about their behavioral observations.
As far as the workload of a forensic psychologist, I can mostly speak for Michigan's system. Forensic psychology is the application of psychology to the legal system. It is typically an assessment focused position, which means that your job mostly consists of evaluating court-ordered criminal defendants from across the state. Each evaluation consists of an interview with the defendant and reviewing a lot of collateral records (e.g., police report, jail records, hospital and outpatient clinic records, educational records) to educate the courts and give an opinion on a few different psycho-legal questions . Those questions are most often 1) competency to stand trial, and 2) legal insanity. Competency to stand trial is a functional evaluation, which means you are examining a person's capacities right now in the room with you with respect to their ability to understand the court proceedings, the roles of court personnel, their rights, their charges, and the decisions in front of them. It also has to do with their ability to rationally assist in their defense, which is related to their ability to appropriately discuss their case, logically weigh potential decisions, provide a coherent account of the alleged offense, and engage with you in an appropriate manner. It is also important here to rule out feigning (in this setting it's mostly faking or exaggerating one's psychological symptoms or low intellectual funcitoning) because this work deals with people who at times believe they have something to gain from behaving in a certain manner to obtain a particular outcome for their case. Legal insanity is a defense that can be used in a trial. It has to do with what was going on at the time of the alleged incident. Different states have different legal statutes of what defines this, but generally a person is considered legally insane if "because of a mental illness or intellectual disability they lack substantial capacity to appreciate the nature and quality or the wrongfulness of their conduct or the ability to conform their conduct to the requirements of the law." If that phrase sounds complicated, it is. There are whole courses designed to break that down and understand the history behind it, so I'm not going to go over it in detail here. Suffice it to say that the weight of the evidence would have to show that a person was actively mentally ill and/or intellectually disabled, which would then have substantially impeded their ability to understand what they were doing or the consequences of their actions, that what they were doing was wrong, or their ability to control their behavior.
I work full time doing these evaluations, and my job consists of interviewing defendants for one to four hours usually, reviewing records, and integrating all this information into a report. Most of the job is reading and writing, so you should both. There's also a less common but perhaps most important aspect of the work, which is testifying in court. Anything you write and submit can be argued over and questioned in a criminal court by attorneys or the judge, and you are the one being questioned about your statements and opinions. You have to be prepared to answer tough questions in a high-pressured environment and be confident in your written statements. Your ultimate job is to educate the courts with your clinical expertise about what is or was going on for this person's psychological functioning that relates to the specific legal question asked. I like to think that we are one small spoke in the giant wheel of the criminal justice system. The wheel can't turn without it because of a long history of case law that guarantees a person must be competent in order for them to go through the court system. If they're not, it's not fair to them or to the integrity of the system and society at large.
There is also mental health treatment involved, though I don't do this personally. When defendants are found incompetent to stand trial or legally insane, they are generally involuntarily committed to a state psychiatric hospital to receive psychiatric care. This includes psychologists (and social workers, psychiatrists, medical doctors, etc.) that work with the patients to either help them become stable enough to be competent and go back to court, or in the case of insanity to help them become a functioning member of society. In this setting you would work on a patient unit as part of a multidisciplinary team and provide therapy and psycho-educational groups, psychological testing as needed, and consult with other staff (and document everything of course).
I really enjoy my job and the people I work with. I have a lot of autonomy and flexibility with my work, which often comes with this level of education and licensure. The job is pretty specific though, so you have to really enjoy it.