There are many different Auschwitz tickets available. If you're coming from Kraków without a car, opt for the Auschwitz tour from Kraków, which includes entrance to the memorial and museum, and a live guide. For fewer crowds and optimal ambiance, opt for a quiet early morning guided tour.
You can also drive yourself without planning a tour, but entrance to the museum is only possible with a personalized pre-paid entry pass. It is free to tour Auschwitz-Birkenau without a guide, but you will need to reserve your time slot in advance.
If you're coming all this way, it's a better idea to explore the UNESCO-listed complex and learn about its history from a knowledgeable guide. One of the benefits of joining a tour is that there's no waiting time! If you don't join a tour group, you might be waiting up to 3 hours to get in.