Study the company and role. Know why you're a good fit for MuleSoft and vice versa. Be prepared to demonstrate a lifelong track of success (qualitative and quantitatively supported), intellectual curiosity, being a good person, and fitting the culture of one of the premier software companies in the history of the industry.
It can take anywhere from a few days to months. Expect around 11 interviews, some of the most rigorous questions, challenges, and vetting you'll ever experience when applying for a job.