What is fastest learning path for learning Power BI?

Hi,

Microsoft Power BI team have made a superb YouTube channel (https://www.youtube.com/user/mspowerbi/videos) and there are lots of video tutorials available from basic to advanced, you can pick the video from there and can learn at your own pace. It is up to you how quickly you complete the tutorials. If you want to get Power BI Instructor-led Training, then you can find MS authorized training provider in your nearby location and get trained along with certification after completing 70-778 exam which will prove that you have earned the required knowledge and skills.