Welcome to the Department of Philosophy at Wikiversity. The question "what is philosophy" is itself a philosophical question that has yet to be settled. If you would like some direction, you can start with definitions, or see what prominent philosophers have called this process of inquiry.
The term "philosophy" comes from two Greek root words: φιλο; or "philo" meaning a (brotherly) love, and σοφία (or "sophia"); meaning wisdom. Philosophers are lovers of wisdom, and more than that, they are persons who never lose the capacity to be amazed, whose biases are always open to review, and who strive to live the Good Life and find its meaning. Philosophy can be understood as a process by which anyone can understand any other field of study or phenomenon, so there are philosophies of science and history.
Basic branches of philosophy include aesthetics, ethics (which are sometimes grouped together as axiology), and metaphysics. These fields respectively ask questions about what is beautiful, good, and true. At times, ontology is thought of as another branch of philosophy, asking what basic categories there are.
By taking a philosophy course, you invite yourself to challenge and refine any and all of your beliefs. You will be presented tools for critical thinking that can open up new worlds in the life of the mind.