It can be in any format, although the CAS Guide does suggest three useful titles: Profile, Experiences, Evidence (CAS Guide pages 30-31).
Although CAS is not formally assessed students provide evidence of achieving the following seven learning outcomes AT LEAST ONCE in their CAS Portfolio. Some of these learning outcomes will be achieved on many occasions, some on some occasions. Note that not all CAS experiences will lead to a learning outcome. The student needs to work with the CAS Coordinator/Adviser to agree what evidence is needed for the portfolio. Often the evidence is in the reflections students make on their experiences. Use ManageBac to build the CAS Portfolio.
Identify own strengths and develop areas for growth
Demonstrate that challenges have been undertaken, developing new skills in the process
Demonstrate how to initiate and plan a CAS experience
Show commitment to and perseverance in CAS experiences
Demonstrate the skills and recognize the benefits of working collaboratively
Demonstrate engagement with issues of global significance
Recognize and consider the ethics of choices and actions
From InThinking CAS