The note-taking tool is not enabled by default. Launch the Edge browser and turn on the OneNote Feed option to get started. More details here.

Web extension If you are a student, researcher, or a power note-taker, you must pick a solution that offers web extension on major desktop browsers like Chrome, Edge, Safari, and Firefox.

Microsoft's Edge web browser has its own extension storefront -- here are some of the add-ons I always rely on for productivity gains.