It's hard to summarise psychotherapy as it has different forms and functions for different people. However, there are some general points that can be made:-
Therapy is time and space focused on setting up causes and conditions to support us to grow and find ways to move forward in our lives.
Everyone has a wealth of inner resources for self-healing, creative problem solving, and living life in an enriching way. Therapy sets out to make these resources more conscious and more accessible to us.
Therapy can provide us with new skills (e.g. mindfulness and self-compassion), as well as new ideas and possibilities that allow us to make the most of our potential for wellbeing, positive action, and a fulfilling life.
Therapy can enhance our self-understanding, enabling us to live with more awareness, more appreciation, and more freedom of choice.